This side business I have with my brother, selling stuff to gas drillers. 5 years ago, we were crazy busy, then it died and it's coming back. Used to sell anything to anybody, but only dealt in truckloads of goods. Got burned a few times. Now , selective on who we sell to and what we sell.....all side money. Pays for trucks and gas and phones and puts a few bucks in our pockets.
Best deal going was to register the cars I built as "Antiques". One time fee of $95 for a new title and plate. Never had to pay annual registration again or get it inspected.