[quote name='Fire']Why of course! Youjust have to wait for a good deal. I personally got Princess Peach as a part of a TRU B2G1 DS sale and the others through BB $10 off coupons.[/QUOTE]
Yeah, but those aren't.. DS specific deals. The TRU deal was for all games (except GBA I think) and the BB coupon was for any title over $30.
The OP seems to be asking for price drops and as far as I see, first party games usually don't. SM64DS is still full price in most places. The crappy titles (Ridge Racer DS, Asphalt, etc.) get price cuts though.
You best bet is to wait for deals like the ones Fire posted. There's an upcoming sale at EB: Buy 2 used games, get 1 free (or equal or lesser value).