A lot less than your budget, but I have been very happy with the Summit 20x50 Spotting Scope I got a couple of years back. Very light, and pretty small which is good if you are somewhere that is a bit sensitive about people peering at aircraft. Cost about 50 quid. Better not post a link to the site I got it from because of the advertising rules, but PM me if you want to know. Suffice to say that it was a camera shop in Yorkshire, and I was impressed that I ordered it online on a Tuesday afternoon, and received it in the mail in The Netherlands 2 days later.