Can i put a pre-paid sim card into my iphone?

My phone contract ended, and I want to put a pre-paid sim card from my other phone into it. Can I do that and still have the same number?

Added (1). It's unlocked. I just need to buy a micro sim for it.

If your iPhone is unlocked then yes, or if your pre paid SIM card is from the same carrier like your iPhone then that also works as well. For example: both are from AT&T.

It all depends on your current iphone carrier if it has a sim card slot it is most likely from att and if the sim card you are tryjng to put in is from att it will work but if simcard is from another carrier like tmobile or simple mobile you would have to factory unlock your iphone which is very cheao prices may vary depending on which iphobe you currenly have from 5-15 $