There are several solutions besides the box you refer to. The advantage of the box is that there are so many options. Whether the box itself degrades the signal via poor connections, soldering, or switches would be a question I might be concerned with. There are more simple adapters that simply adapt RCA to XLR. The better ones are made by Neutrik and often come with BAT components (I think BAT markets the Neutrik adapters under their name). You can also find cheaper adapters at the local Radio Shack or electronics supply store. I don't know if these are identical to the BAT/Neutrik adapters, but they are only $10.49 each on this site, which is a world away from the BAT price, and they are made by Neutrik:
http://www.markertek.com/MTStore/product.CFM?BaseItem=NA2FPMM
You can also find some cable makers that will make, and do market adapter cables with RCA on one end and XLR on the other. Stealth Audio is one, and I use their CWS (cross-wrapped-silver) cables to go from my single-ended CD player to the direct input on my LS2B. Excellent cables, but would cost at least double your budget. They do come up used on Audiogon but still tend to go for more than $140 a pair. The adapters would be the cheapest solution. Remember XLR come in both male and female so make sure you get the right one for your application. I believe you'd loose the advantage of grounding that the XLR to XLR connection would otherwise provide if you are going from (or to) single ended. Someone correct me here if I'm wrong.
Good luck!
http://www.markertek.com/MTStore/product.CFM?BaseItem=NA2FPMM
You can also find some cable makers that will make, and do market adapter cables with RCA on one end and XLR on the other. Stealth Audio is one, and I use their CWS (cross-wrapped-silver) cables to go from my single-ended CD player to the direct input on my LS2B. Excellent cables, but would cost at least double your budget. They do come up used on Audiogon but still tend to go for more than $140 a pair. The adapters would be the cheapest solution. Remember XLR come in both male and female so make sure you get the right one for your application. I believe you'd loose the advantage of grounding that the XLR to XLR connection would otherwise provide if you are going from (or to) single ended. Someone correct me here if I'm wrong.
Good luck!