What’s the Best Way to Spend $20/Month to Experiment With AI?

I don't want to pay for multiple pro accounts, such as Claude, ChatGPT, Google Gemini, and Microsoft Co-Pilot, at the same time.

I've noticed there are services like You.com, Vercel AI, and Poe.com that claim to give you access to multiple models; it seems like Perplexity does as well.

There are also apps like Merlin and Chathub.

Are there downsides to doing it this way?

Is there one that's recommended within the community?

Thanks!