Air perssure Light. Help

ok i just bought a used 2006 tundra SR5. i noticed the air pressure light on. found out the truck didnt have a spare, so took back they installed one, the tech said if i take the truck to a tire shop with a number he gave me said they could reset the light. well the tire shop said they couldnt do it. so i called the dealer they said i have to get the truck reprogramed. a few hundred bucks. i tryed the button under the dash hel untill flashed 3 times, light still on. so how do i reset this darn thing? there has to be a back door to do this without going to the dealer, so what if you get diffrent wheels and tires? any help on this please.

Any shop that has a higher end OTC scan tool (or mac mentor/pegasys) and a TPMS scanner will be able to reprogram the TPMS module for you. There is nothing you can do without an O.E. scan tool or the OTC scan tool.