This must be a more complicated question than I thought. I always thought it just meant, I had a choice.

Of course it does. Your free will chose to be on this site & put this post up. It's that simple! Decisions and choices are made by people's rational thought, or sometime lack there of. We are in control unless there is something holding us back which could be deliberate and that would entail a lot of variables too detailed to explain.

Technically, everything we do is the result of some complex combination of our biology down to a molecular level, environment, and past events, so technically, No, free will is an illusion. But it is one that we absolutely can live with. On a personal experience level, we enjoy the experience of making choices as we see fit, so "effectively" we do have free will, even though technically we don't. Clear as mud, right?

Dan dennet and Sam harris do well on arguing this.

I feel free will exists. But getting to exercise your free will is damn near impossible in todays society. With all the mental manipulation viewed through our perceptual field, I seriously doubt people have the capacity to understand they have lost thier free will. We've traded it for a propaganda, media induced, corporate government regulated comfort blanket.

The balls that pop up in a lottery machine are not random. Knowing the location of every molecule in the tank and all forces that are in effect, we can deterministically say which numbers will appear. However, it is "effectively" random, because we do not have all that information or the methods to glean it all and process it. I believe we have "effectively" free will in the same way. We are susceptible to manipulation because variables we do not yet understand affect us, but we should operate as if we have free will because that is necessary for "morality" and whether free will or morality exist in the terms we believe now, they are beneficial in an evolutionary sense.

Free will at the individual level exists. We can choose what we want to do. However the overall effect, that is to say the output of our decisions, is exactly the same regardless of what we do. I do not mean "the same" as in if I kick a soccer ball it will bounce and roll in a roughly straight line vs if I kick a rugby ball it will bounce randomly and won't roll as far. I mean that you converted potential energy to kinetic energy, this makes both occurrences the same. This is true with life.

According to the meaning and purpose of life, we individuals control our decisions and choices. However the meaning and purpose of life is what controls us. it gives us free reign to do as we please as long as we abide by it's rules within it's domain.

Long story short, you have free will to an extent. If you re-discover the meaning and purpose of life then you will know what I mean.

The opposite of free will is determinism - where everything happens in a mathematically predictable way.

My answer: Chaos theory.

Basically, Infinitesimal differences in the original conditions lead to completely different outcomes. Nothing, according to the Heisenberg effect, can be known with absolute precision. Combine these two and nothing can be predicted with certainty. So whatever it is that makes you YOU, and whatever you do, is fundamentally unpredictable. You are free.

At the risk of introducing maths here, try a very simple iterative equation.

(You will need to make changes for this to work in a simple computer program because of the way computers work.)

Take a number 'x'.

In each iteration x changes by being multiplied by something - let's call it 'R'.

So x(next) = Rx

Example: If x = 3 and R = 2 then x(next) = 2x3 = 6

Next iteration: x(next) = RX = 2x6 = 12

and so on

But what if there is a maximum value for x

Imagine that x is the number of fish in a pond which can only support 1000 fish. The greater the number of fish the more die. Each year (iteration) the fish multiply (multiply the number of fish by R) BUT the number of fish which die depends on 1000 minus the number of fish in the pond.

So the number of fish dying is proportional to 1000 - x. (If there are 1000 fish they all die and if there are 0 fish none of them does.)

The equation is:

x(next) = Rx(1000 - x)

You take the number of fish, multiply it by their reproductive rate and then multiply it by the capacity of the pond less the number of fish.

If the reproductive rate of the fish is low then they eventually die out. A greater rate and the population settles down to some value. The greater the reproductive rate the greater the value. But then the number oscillates each year between two values. A greater rate still and it oscillates between 4 values. A bit more and it oscillates between 8, 16, 32 and so on values.

Here's the point: At a certain point the number will not settle down at all. It will swing chaotically. After 500 iterations (years) it is not possible to know how many fish there will be.

Here's the second point: (This is maths so I can have a fraction of a fish) if the original number of fish is infinitesimally different (i.e. 2.00000000000000000000001 fish instead of 2 fish) the number after 500 years will be completely and unpredictably different.

You fundamentally can't know the original conditions so you fundamentally can't know the outcome.

Free will?

Since any decision/action is based on previous experience/knowledge, and awareness (hopefully) of consequences, then it can be demonstrated that, if someone knows you well, and is aware of the circumstances, they can predict accurately how you will behave. This precludes you being aware of the prediction process. ) Since people are predictable generally, and as on-line shopping has shown, at an individual level a lot of the time, free will per se is very unlikely. Yes, it is possible to do something different to predictions, but that could be predictable if your state of mind at the time was known, from observable behavior. "Being difficult day".

Language is a relatively new phenomenon for the naked ape, yet look where it has taken us – from the Pleistocene to Pokemon Go in a few tens of thousands of years. Our early development is shrouded in local cultures and language and there doesn’t seem to be much free will to any of it. Someone gives us our name, our social standing and education prospects right at the start of our journeys and we then, generally, play out the narrative we are given. Sounds harsh, but for the most part it’s true. There’s always exceptions to the rule, those that buck the trend, but for the most part, those in charge of the game (and the rules) are the children and grandchildren of those who were in charge of things in their day. We know this, but we shrug and accept it. Curiously, we don’t like people who deviate from the norm, we’re trained to ostracize them, yet it tends to be individuals with smart ideas that effect good change, not groups of people. We find them curious.
There is a biological reason for a lack of free will and it’s tied in to our pattern seeking nature. In the west our basic drives for food, shelter and love have generally been met, even though we’re not fully aware of that all the time. This is important because it creates a culture of want, rather than need, which is a subjective state. We’re not jealous because someone has food and we don’t, we’re jealous because they have silver cutlery and we don’t. Those are abstracts that tickle our unfairness buttons, allowing us to get worked up, but ultimately not crucial for survival. It allows us to be unconcerned for those below us on the tree of life, while justifying the lack of equity directed our way from above. Fairness is subjective and all the better when we can justify it. All the big questions (like Who am I? What am I? Why am I?) are taken care of during development: Why you’re Bob; your dad was a blue collar worker who didn’t get to university; you have less chance than Bill, but if you work hard and pay your taxes, you could be Bill. The American dream. But it doesn’t exist in practise.
In order for us to get through life without going insane, there exists a number of cognitive biases and ego defense mechanisms which we all use to varying degrees, simply so we might constantly justify ourselves to ourselves. In cognitive biases and ego defense mechanisms we can find the real motivations for ignoring homeless veterans on the street while allowing billionaires to take all our money. And it ain’t free will. [en.wikipedia.org]

That's one hell of a question

If action determinism precludes free will, then no, free will does not exist.

Everything we do is impacted by something. So, I say no, there is no such thing as FREE will.