no. You only get the "cheap" price if you are available for an upgrade, i believe.. Otherwise, you would be better off selling your existing iphone and tkaing the cash and buying the 3G.. HOWEVER, before you decide to go in and buy the 3G, i suggest looking up and figuring out your 3G coverage. You might be happier and better off waiting for 3G coverage to be better in your area and holding on your existing iphone.
If money is NOT an issue, the IDEAL situation would be to purchase a 3G (16GB ofcoarse) and use that one for a while, but KEEP your older one just incase you decide to return, you still have the older one (since you can not buy the 2G new anymore)
For me, personally, 3G is USELESS> we have NO COVERAGE in our area, and i already have a GPS unit, and my internet is pretty fast.