I have a DS-2, which can record stereo and in very high quality. Satisfying unit which I can recommend.
Mac compatible software is included, also a dock to connect to the mac. I haven't installed the software yet, so I can't tell you details.
I wouldn't go with the cheaper ones, as they mostly are PC only.
I got the ds-2 from amazon, can't truly remember the price, somewhere below 95$, but it is easy to use. I recommend getting rechargeable batteries.