Like many people, I own a Nintendo DS. If you’re tired of all the games available at your local electronic store, you can check out Homebrew games. Homebrew are games created by people, not companies, and are available for you to play at no charge. With Homebrew games, you’ll need the assistance of a flash Cart.
So here are three popular flash cart.
The R4

The R4 is exactly the same at the M3 Simply. I highly recommend this cart over the M3 Real. It’s easy to use and almost compatible with all the homebrew application out there.
The M3 Simply

This is my flash cart of choice. It’s easy to use and fast to load programs. The size of this cart and the R4 is a perfect match as a regular Nintendo DS game. I would recommend this, but unfortunately, this is no longer manufactured.
The M3Real

I really don’t recommend the M3 Real because of loading issues. Programs would often freeze and a restart is needed. When it chooses to load your program, it takes forever, about twice as long as the R4. This cart is also a little chubbier than the other two. That means that the contacts on the cart don’t always meet the contacts on the DS.
If you want to purchase a flash cart and try out the Homebrew applications, just google them and you’ll find many online retailers.