Which sim card to get for iphone?

If i just want to use the iphone for internet (when i have a Wi-Fi connection) WITHOUT a phone plan… Do i need to get the prepaid micro sim card or the postpaid micro sim card? Or does it even matter

You shouldn't need a sim card

Don't get an iPhone if that's the intent. Get an iPod touch instead.

An iPhone will work without a sim card on Wi-Fi. You don't need a sim.