No way that most of your choices can be the FIRST 10 in your garage, GT5P adn GTPSP cars will only be available to Arcade mode.
GT usually has about 10k credits to begin i think GT5P has 15k. So you're forced to buy one entry car unless you ace all license tests(assuming they award cars for each license).
So thats 9 to choose, except, once you start racing, you win cars, so within a few hours you have yourself 10 cars comprised of one purchase and several awards.
First most basic races are the Drivetrain races asi call them FR FF 4WD MR (RR will hopefully be acknowledged this time!) so you win one of each. Thats 6 including the starter.
Then you have the Engine races, so youll have one NA one Turbo one Boxer. 9 total.
1 left.
And i doubt theylll be giving away McLarens and LP's and 458's for B-A license races!