Leave a Legacy is a project at Epcot where you get your picture taken and they engrave it (and many others) onto these large metal plates that are mounted to these granite (I think)... uh, things. Granite statues? Granite upshoots? What in the heck would you call those?
Yes, it does cost money, it's in the realm of $40 if I remember correctly and it hasn't changed. You can get a discount for various reasons (AAA, DVC member)