Did you want to develop a domain reg price site yourself? If that is true then, very nice choice, and obvious higher value.
In the non-domaining world, it could also be short for Regular like a comparison shopping site telling you if a deal is good
Reg could be a nickname for Reginald, Regina, etc there might be a person with that name, ok a few scant few but worth a shot to enduser might love it.
And registration could apply to cars, businesses, college or schools, it might be too generic for these though.
Agree low to mid $xxx