Don't do mate's rates, freebies or cheap work on the promise of bigger and better jobs in the future.
Where to advertise?
Car shows - take along some examples of your work.
Local papers - tend to be the first place a lot of people look
Web site - don't mess around with GoDaddy and crap like that, get a site built properlyy (drop me a PM if you like). Do not rely on a Facebook page - it's amateur hour.
Local radio - not always as expensive as you think and VERY effective
eBay - list your services as items with a buy it now price. Just about allowed under their terms and conditions but word your ads carefully.
Car magazines, other forums etc, etc