12" x 12" tiles are about 60 cents to $1.00 each, 18" x 18" tiles run about $1.50 - $2.00, at Home Depot, Lowes, or any of those big home/garden stores.
Nothing that's glass, or has glass in it. Most glazed tiles will be really slippery for them. Talk to the associate of waterever store you go to, tell them that you're putting it in a reptile enclosure so you need to make sure that the tile can be very close to heat, and absorb it, not reflect it.
Most tiles that are ceramic will not reflect heat, so any of those would be fine. I am not positive about porceline tiles, and any type of slate tile would do just fine.
Just make sure to run your hand and even nails along the tile to make sure it's not super slippery.
Ok sounds good! He's going to be getting a new cage soon so i think ill wait till then to make the move instead of stressing him now with a substrate change and then a cage change...not that i want to stress him...but i think it would be better for all if he only had one change