So I'm looking to pick up a Captivate by the end of the month. It just occurred to me that since I'm eligible for an upgrade that I could buy a 32gb iPhone 4 for $299 and sell it on ebay for a lot more. Afterward I could just buy the captivate at the no contract price that at&t offers (~$500) and use the extra money for a micro sd card and whatever else I want. Has anyone else done this? Are there any problems with doing this, such as at&t not allowing it? I assume there shouldn't be a problem but sometimes companies have some fine print that you would never expect. Thanks.