The '07 and newer Tundra does not have torsion bars to level the front with. You will need a leveling kit (strut extensions) which is about $130.00 from
www.roughcountry.com most shops can install this with with no problem in about 2 hours. Or, if you have any mechanical ability you can likely do it in the driveway in 2-3 hours.
As far as tires, your stock tires are larger than 30 inches. depending upon which factory tires you have they are 31.75-32.1 inches. With the leveling kit you can move up to a 33 inch tire. Tire pricing varies widely by what you want brand, and style wise. If you need mud tires and want BFG's it will cost more than Fuzion brand street tires in the same size.