Change your oil- yourself or shop

I have the Ford V-10 and do it myself, even if it's on the road. I stop at Wal-mart and grab the Motorcraft brand oil and filter, then change the oil wherever it looks like I'm not going to create an issue. This has included the parking lot of a Marina, several abandoned lots, rest stops and roadside pull-outs, and most recently, while parked in a friend's yard. I put a small plastic tarp down, make a catch chute with cardboard to guide the mess into the catch pan. Typically, I don't end up with a dropped spilled on the ground. The oil and filter cost $30, and I have been quoted from $60 to $169 to have it done "professionally". I save a few hundred a year doing this, and know it's done right, with the proper materials.