In general, go for a lower magnification. Anything over 10x is going to be shaky freehand (unless you’re well practised), plus you’re going to need a big lens to collect enough light for dusk
Personally I’d aim for 8x
If you’re not fussed about brand, but want quality, you could look at some of the Chinese manufacturers. They’re not on par with ze germans, but they’re excellent value for the money. You’ll find something in your price range too. (I’m talking about the good Chinese manufacturers like Zen Ray, not the cheap ones)
I have a small pair of Leicas (8x20s) and some bigger Zen Rays (ZRS 8×42), both excellent
Spotting scopes are much point unless you’re spotting something in general, and you’ll need something to stabilise it. If you’re scanning you’ll probably needs bins anyway