PrepRate is two English words.
The way its written for the nonnatives
preprate it looks like a misspell. Or PrePrate. All the same letters but not really getting the same reactions!
Evaluation:
If an entertainer started saying "PrePrate" and sounding it out like that you may have a nice window to sell for XXXX. Ofcourse just because its possible does not mean it is probable.
PrepRate could be a nice catch phrase for say soccer or baseball costs for an age group. Prep schools are a thing.
I doubt anyone comes looking for this one. Reg fee is likely, but I think to domain investors you might be able to get $50 . . . not rom me though! Right person right time, $500 seems most likely ceiling if it were to sell.