That is the best way to get them done, by painting them. I got a spray gun, so I ended up taking them off the car which made it easier to get even coverage on both taillights, backing lights, and even the reflectors. In order to get them tinted, you have to add a little black to the clearcoat mix. I ended up using a red candy paint with black toner to darken.
The vht nightshade is the cheapest way to go followed by some clearcoat aerosol, a bodyshop will most likely want to charge $80-$140. The paint I bought was only $10