Actually had 5 Guys for lunch today. A little cheeseburger (for me), a hot dog (for DD), one regular fry order, and one 20 oz drink was just over $11 including Florida tax. The regular fries are large enough for DD and me to share with plenty of leftovers, and there's free refills on the drinks. If DH is with us, he gets the bacon cheeseburger and we get the large fries instead of regular to share. It usually comes out around $20.
DD loves the shelled peanuts and it's a great way to pass the time until your number's called and your order is ready. I wouldn't drive 50 miles just to go there, but if you're over that way I think it's definitely worth checking out. Everybody we've introduced it to has loved them so far.
Edit: Yeah, this is very much not a place to go if you've got peanut allergies. They do post signs inside and out, but there are peanuts to shell up by the registers, and sometimes people throw the shells onto the floors also.