I have used Argos
who did a superb job but are premium prices.
are aslo meant to be good.
Expect to pay around Â£60-Â£80 for one plain colour.
Maybe Â£10-20 more for metalics and pearlescent colours.
That includes base coats, preps, primers and lacquer so additional colours are about Â£20-30 more.
Applying decals adds about Â£15.
I would always go for postage. They cand courier much cheaper than you or I can send through standard mail.
On the outside it looks quite cheap, but add a second colour, in a funky finish, oplus declas, plus postage and it can add up.
A basic colour can be powdercoated for much less, maybe Â£40? Not quite as flashy but more hardwearing.