FWIW - I've seen prices on trailers from national companies as low as $4.00/sf installed and I've seen others who charge $10-$12/sf or more, so it's really all over the board. If you're new to wrapping, you have to understand that your price and what you have to charge has nothing to do with what other shops charge and what they have to charge. Price your work out based on covering your material costs, labor and machine time as well as a healthy dose of profit and don't worry about what everyone else charges.