Free: Contests & Raffles.
nikon buckmaster is a really good scope, I think its in the $300 range. look at the reviews on it- all good things
Fall City Firearms had a pile of Leupold VX-1 3-9x40 for $219 at their grand opening a week or 2 ago. They said that was $30 cheaper than Cabelas.
Depending on your price range, I'd pick the best Leupold you can afford. You will not be disappointed and have a lifetime warranty that they honor well.