You don't need money
Depending on the laws where you are, once you buy the console, modifying the hardware or firmware should be perfectly legal (modifying the hardware is sometimes looked down on), so you can get guides on the net for how to set it up to play Homebrew code.
You're going to need to learn C++, some level of advanced (Discrete) Math / Linear Algebra, how graphics systems work, and then you'll have to learn all the neuances, syntax, and quirks of whatever homebrew library package you're using to write the game.
Personally, I make games for the DS more than I make games for the PC now, I just love it so much.
I quite often use DBP as a fast prototyping tool, and even to write tools to help me make games
For example, I need images to be in a particular format for the DS, so I used DBP and its Memblocks to load in an image, read it byte by byte, and save it out as the desired file format. Allowed me to get a really easy to use application knocked up in an hour