It appears to me that not having a vehicle is a major problem for you. In order to best decide what kind of vehicle you will need, you first need to identify what kind of work you plan to go after, and what equipment you will be hauling.
But as a basic starting point, I'd look at a full size pickup with a v8 engine. Sure a smaller truck would work for the time being, but you just don't have much room to grow, weight and equipment adds up fast.
Where to get a vehicle? Look in the same places you'd look to buy any other kind of vehicle. Get yourself a Tradin' Times magazine and start there.