Old Iphone SIM in new Iphone

I have 2 questions. Just recently I cracked the screen on my iphone which is the original iphone. The top line of the keyboard stopped working yesterday and I have tried re-setting it but it is still not working. I was looking to get a new one but don't want to switch my plan. Can I buy a new iphone and place my original iphone's SIM in there? Also the prices for the new ones are just crazy but I found a site that is selling the 32gb 3gS for $99 without a plan .Apple iPhone (32GB) iPhone 3GS [iphone3gs] - $99.99 : ITSINSTOCK.COM, One stop Accessories shop!

Does this look right to you guys?

Any help is appreciated. Thanks a lot.

If it seems to good to be true......
I see no way that this can be a real offer for a real new iPhone 3gs 32 gig.

Stick to craigslist or ebay. That website is most likely a scam.

Yes when you buy a new iPhone you can put your old sim card into it.