It is ok, but i would prefer a PSP [Play Station Portable] as the cost of the games would be nothing.
The prices of the Nintendo DS games are between 160 - 240 Q.R per game. The PSP games are in the same range, but ... you can modify your PSP for <100 Q.R and then download games from the internet and save your money.

With Nintendo DS you can't do the same and has to buy the original games, some do have other ways to do so but i have no idea.

The prices are [Consoles]:

Nintendo [DS]:
600 - 700 Q.R

PSP:
700 - 900 Q.R [dude to different packages, some with games, some without]