I think you can start with the Hobby plan. If it's not enough, then you can upgrade to the Pro plan.

for a telegram bot with payment system, hobby plan is more than enough and you'll still have plenty of budget left over. here's the actual breakdown:

hobby plan = $5/month subscription + includes $5 usage credit. so you pay minimum $5/month but the first $5 of resources (cpu, ram, bandwidth) is free. if you use $7 total resources, you'd pay $7 ($5 base + $2 overage).

telegram bots are super lightweight - most run on like 100-500mb ram and minimal cpu unless you're processing thousands of messages per second. the hobby plan gives you up to 8gb ram and 8 vcpu per service, which is way more than a typical bot needs.

with your $20 budget, you could:

run hobby plan and have $15 buffer for any usage spikes

or go pro ($20/month with $20 included credit) if you want the extra limits, but honestly overkill for a standard bot