If i buy an iphone 5s without a plan can i use it?

What i'm asking is, if i buy an iphone 5s on apple.com and i get it and everything, can i take my sim card out of my iphone 5 and use it on my 5s will i get service and everything?

If you buy an unlocked 5S, yes, it should work with the SIM card from your iPhone 5.It will work with Wi-Fi even without the SIM card. Make sure you buy your 5S in the same region where you bought the 5, as the exact radio bands vary somewhat from country to country. Contact your cellphone carrier for details on how to make the SIM work in the new phone (although usually it's just a matter of inserting it).