haha, closest ones are 45 min drive down the interstate.
i forgot to add, i've never worked with coins before,
Banks often have half-dollars as well.
Ask your parents if they have any half dollars or old silver dollars you can work with. If that's not an option, banks will trade equal value when they have the coins, i.e. two Kennedy Half dollars for one dollar.
It's not a guarantee they'll have them, but it's cheap.
Also buying effects from magic dealers will give you the coins you need.
You could also practice with quarters. I find that my ability to classic palm quarters and nickels helps when I don't have any coins on me, just borrow and go. It's a lot of work, but it pays off in the end.