According to Starlink's website the RV dish costs $599, which is the same cost as the residential dish. As far as I know, the residential dish can be used with the RV plan and vice versa, because it's the same hardware.

Currently the only $2500 dish available is for the "business" plan. Starlink will be offering a new RV dish that can be used while in transit, which I suspect is where the $2500 number is coming from. The current $599 hardware should still work, albeit while stationary.