I recently bought several copies of STO from a Sears and I was able to use the code printed on the manual for the first copy. It gave me a 30 day gold subscription and some Xp and some Zen too I think. I tried another box and after entering the code I got a message that the code had already been entered. Why was this the case? Are you only allowed one of these codes per account?

You can only use one cd-key per version per source attached to an account. For example, you can use a cd key from Best Buy, one from Walmart, one from GameStop, etc.. You can also use two cd keys from the same source as long as they are different versions, like a Best Buy Retail and a Best Buy Collector's edition, but not two of the same source & same version.

You can use them on additional accounts if you have them. You could also try to return the unopened ones. If you are feeling especially generous, you could send me the code for the second one you opened, since you can't return it.

Interesting. Thank you. They were bargain bin sales so no returns. I may use them to cretea foundry contest.