Couple of things:
1) I've never owned the 50-200, but I can tell you the 18-55 is a pretty good lens. I've gotten plenty of great, sharp shots with it. No, it's not a Limited prime, but I wouldn't kick it to the curb until you've tried it. It's true that there are substandard lenses out there. On the other hand, plenty of crappy photographers blame the gear for their own shortcomings. I frequently see bad reviews of long tele lenses with blurry example shots of flying birds. Then when I look at the exif data, it says they were shot at 400mm at 1/50th of a second or something. You gotta read between the lines & don't take every review as gospel truth.
2) I have
this macro lens. It's a terrific performer, it's true 1:1, and it's cheap. Also available in an AF version with lower build quality but the same glass. Personally, I wouldn't want AF on a macro lens. I prefer the MF version. Just make sure you get the 1:1 diopter that comes with it if you buy it used.
Good luck,
Bobbo :-)