How can I put real cars in GTA San Andreas?

You'll need the PC version.... go on various GTA websites, like TheGTAPlace.com... in the downloads section, look up GTA SA car mods.... install them in and they will replace the cars you have... SA has plenty of cars to replace, but some mods may not work if you don't have certain programs.

you can't put real cars in the game, just drive the cars currently in the game.