Depends on the market, quality of film used, and the type of install--obviously the parts that you want covered (amout of film used).
Like detailing, make sure that you know *exactly* what is covered. One person will quote a "full detail" which consists of a wash, wax, vac, wipe, dress tires. A "real" detailer plans on spending at least a day on the car.
When getting a quote for ppf ask the installer what he/she considers a full kit. We have installers around here that quote a full kit and the price seems really low because they install "bikini" kits and upsell the "full" kit. Also, do you want it wrapped? Does anything need to be pulled in order to wrap it(lights, grills)? Will you want any custom pieces? Anything that the plotter will not spit out will be more as it takes time to fabricate.
FWIW, we use mostly ventureshield ultra and would charge about $975 for a "full" kit(more or less depending upon degree of difficulty). That would include hood (at least 20"), fenders, front bumper, lights, fogs, mirrors, door cups, and a rear splash piece.
Hope this helps......