I have activated the one month free trial for membership so I can try out the gamefeed API. But when I POST with my email and token, it responds with

"error" : "This API may only be used by members"

Do I just need to wait until it recognizes the change? I activated membership about 20 minutes ago. If so, how long should it take?

Wait for about an hour then it should work.

Unfortunately someone abused it in the past so I had to turn off API access for trial memberships. API access only works for members who have paid. Contact me with what you're trying to do and we can work something out.