I would highly recommend both Dresscode and Akellian Envelopes. While I'm sure Regeneration is a powerful effect, and it looks awesome, what you're getting there is a single trick with a limited number of uses. If you've only got $50 to spend, I think Dresscode and Akellian Envelopes are a good way to go. Dresscode is super fun to play around with and come up with ways to use, and Akellian Envelopes are an incredibly powerful tool that can be applied in numerous different ways. Both are very well thought out, and the instructions are thorough and clear.