Do i need a brand new sim card for iphone?

I recently bought a used, iphone 4s from ebay and it has arrived.
do i need to buy a totally new sim card for it? (i haven't opened the box yet, until christmas) or can i use the same one i used for my samsung?
does apple have special sim cards that you need to buy for your iphone version?

IPhone's and basically all the high end phones need something called as a Micro SIM it's nothing special actually just goto a cell phone shop with your current SIM card, the vendor will cut your SIM into a Micro SIM.