Yes, you can purchase extra tester credits even if you're on a subscription plan with Userbrain. This provides flexibility for users who need more testers than their subscription plan includes. It may happen that you run out of your monthly sessions or you just want to collect more feedback videos than usual, you can always buy additional credits for $39 each. Here's how you can do it:

If you want to run more tests on a monthly basis you can always upgrade your subscription.