[userabchn]

Before paying for mock interviews, it might be a good idea to first get practice with something like https://grow.google/certificates/interview-warmup/

[baka367]

There are also plenty of virtual groups around that offers p2p interviews (each side interviews another).

These might be better for initial warmup as the only cost is an extra hour of your time (but it also allows you to experience the interview from the interviewer's perspective).