Buy 3GS now full price, another later at discount, then sell it?

[psymac]

Will upgrade to 3GS at subsidized price on 7/29, thinking of buying a 32gb 3GS now at full price, use it for a month, and then sell one of them on ebay or craigslist after 7/29 (and probably break even or nearly so).

Best way I'm thinking is to activate the subsidized 3GS on 7/29 and then sell it as new. Or should I sell the full price one I used for a month? Would I then just switch the sim cards and do I have to do anything about the IMEI on either phone?

 

[TheGoog]

Or wait a month, and save a bundle! The 3GS is a great phone, I love it. But it's just a phone and considering the hit you'll take reselling, a month isn't that terribly long to wait.

 

[JVV33]

I was actually hoping to do the same thing. Anybody have any advice or experience with this? Thanks in advance