When I first started playing my Tex-Mex Strat I was hanging out with someone who had a rack effects system. He had gotten it for a very reasonable price. I liked the sounds he was getting so I decided to look for an inexpensive way to add some 'color' to my sound. I ended up buying the RP-3.
The good news is that the RP-3 is a good little multi-effects box. For the $s you can't go wrong with this box, especially if you are a beginner.
The bad news, at least for me is that I spent way to much time fiddling with the settings on the RP-3 than I did practicing. And even though the RP-3 has a lot of different effects, most of them are only 'ok'. In the end I sold the RP-3. I use to maintain a page of patches. But since I sold the RP-3 it doesn't make sense to maintain that page anymore.