Price limits mean little, especially if we're talking the difference between a good clone for $40, and a crap one for $30.
If you've never built a genesis type RBA before, I suppose you could do far worse than an RSST to start your education. Look for the pyrex glass version.
Personally, if you want something other than another KFL/R91, I think you should look at the Taifun GT... which has been pretty accurately cloned by most, then the sQuape... which is still a bit of a hit and miss, depending on the cloner. Again, glass tanks when possible.
Good luck ;-)