That's the problem right there, can't afford one so I have to make due with what I have.
Most people can budget for it, but don't want to give up other things in their life. If you actually want to do that, you can cut out fast food, coffee, sodas, etc. You can also cut back on certain things around the house, if at all possible.
This kinda coincides with people who say they don't have enough time to work out. Most of the time, you can make time no matter how long your days are. In a lot of situations, you can scrounge up $25-30 per month for a full gym membership. I do understand if you truly don't have the money. In that case, you're not likely to put on much muscle, but there's plenty you can do to improve your strength, endurance, and overall health.