Generally spoken - no. Reason for this is that paid scripts are bound to your account and according to the ToS you're not allowed to sell your account. On top of that editing the script to work with other accounts but yours is considered cracking and ultimately will lead to a suspension of your account.
In fact there are some authors who indeed allow reselling their scripts and even ownership changes (= the authorized account will be changed, allowing you to sell scripts you used to use before). I'm not quiet sure but I think Manciuszz, Klokje and burn allowed this. Just shoot them a private message at BoL forums to make sure you're allowed to resell your license