sold me my Juki DNU-1541S at about as good a price as you will find. Service and support have been excelent.
I have had very good luck for the most part on eBay, but it is hard to tell just what you are getting from the photos sometimes. Something that looks OD on your screen may be a tad closer to forrest green than you wanted when it shows up, that sort of thing. Usually, it is not so bad a deal and you can use it, but it can be a bit of a crapshoot. Remember: most designs for gear use materials in places that it cannot be seen, so this might be a good place to use materials that are a bit off-spec in color, etc.
If you have a Northern Industrial store near you, they sell tarps made out of various weights and colors of Cordura that can constitute a pretty good deal sometimes. Man, some of those colors can be pretty funky though. :-) I have obtained perfectly servicable black, browns, tans, royal blue, international orange and OD green that way. I passed on the fuschia and neon puke green, though :-)