You'll have a hard time making money doing that.I've worked in the automotive industry for 15 yrs and have heard many,many discussions on making that profitable.You would have to charge $100.00 for an oil change.think about this,cost of truck,insurance for truck and as mentioned liability insurance,cost of parts and gas for truck to go mobil and your not looking very profitable.The $19.95 oil changes usually end up costing the consumer $39.95 and up after upselling(wiper inserts,air filters,in-cabin filters etc) and it would be hard to stock those on your truck.Plus there would be another expense inventory.I am actually looking at a business start up right now and I am thinking about a $5000.00 initial investment(I also have a partner) plus planning on no profit for at least 6 months.Good luck though and don't give up the dream of owning you own business.Somebodys got to be the next rags to riches story why not one of us?Just my .02 worth.Ended up being about a quarters worth though.