Do I have to sell my iPhone 4s Sprint with the SIM card?

So I'm looking to buy a used iPhone 5 for Sprint off of eBay. I've done this before with an SG3 and my iPhone 4s. Both I took and got activated. I didn't even know my 4s had a SIM card because Sprint doesn't use them. When I take it out, however, my 4s says "no sim card" and my service goes away. So it does use it.

Now if I buy an iPhone 5, that doesn't have a SIM card, can I put the one from my 4s into it?

The phone isn't using it technically but you can't really get rid of it. Sprint is a CDMA network and the card is basically just there because it needs to be there for the phone to work because the 4S is a CDMA and GSM phone. It doesn't have anything on it. Putting it in another phone would do nothing.