Make sure you read the terms and conditions when using an Apple discount. Some require that you keep the machine for a specified time and cannot sell it before then. I have to wait til the end of the month to sell my MBP because I got it with an Apple employee discount and have to keep it for 2 years (and they will check that when transferring stuff like AppleCare). Corporate discount, student discount, and developer discount all require you keep the machine for 1 year. People have gotten flagged for selling their systems early and they are not eligible for the discount again due to the violation of the terms.