Personally, I would look for a used machine from a major manufacturer. Your budget would probably find you a decent machine if you bide you time. I've never liked the look of the marchant dice machines, but never owned one. I know if you search their site everything is way more expensive than anywhere else. I've opted to build my own machine and this has had its merits and downfalls, however, if you have the time and inclination then you can build a machine thats perfect for your requirements. There are plenty of build logs on this forum to help you on your way.

If you search the popular auction site, you will more than likely find a few machines.