Unfortunatly, the "you get what you pay for" rule applies huge to optics, especially spotting scopes. For $300.00 I would look high and low for the oldest Bushnell Spacemaster I could find. And by old, I mean early '70's vintage and made in Japan. Fantastic spotters for the dough. IMO the optics are easily compared to new scopes worth twice as much.
R.
Konus is a really good value spotter.....
http://www.championshooters.com/Scopes-g.htm
http://www.jarheadtop.com/KONUS.htm
Need it to see out to 800m and mirage...