You can't! But, you can buy them in easyedge or you can find them on the internet. The only 'free way' is for someone to possibly bluetooth a game to you.
Unfortunately there is no way to put games on a phone or hack it's interface to accept games. The cell phone company and the game's developers/publishers all have to get paid. So it's not quite a surprise that games as old as Tetris itself can run 6 dollars and higher. On the plus side, these games give you unlimited use once purchased for as long as you own your existing phone. There are certain games that vary among cell phone providers which either feature timed (such as 1 to 5 minutes) or 1-day demos. In most cases such demos are free and include the "full" version of the game, however if you want to keep playing you'll have to purchase the game. It's quite hard to buy games that you may never have the screenshots to or had an opportunity to try. The following link may be able to help you with information, gameplay tips, and screenshots:
http://www.gamefaqs.com/portable/mobile/ this is fubbish