IMHO, the best scopes for the money are the Bushnell/B&L Elite series. Someone recommended the 10x40 elite, which is a fine scope, but not for most coyote calling situations. To me, the object of calling is to get them in as close as possible. Most of the coyotes I've killed were within 30 yards. I'd hate to think I had to pick up those close, hard chargers, with a 10x scope.
I'd say to look at something along the lines of a 3-9, 2.5-10, or the 4-12.
I've used Tasco, Simmons, etc. in the past, but I replaced them just as soon as funds allowed. They served the purpose, but I just didn't trust them all that much. I had parallax problems with two Simmons 44 mag's, but Simmons replaced the scopes. It was kind of a hassle to ship them back.
You'll get a lot of recommendations for Leupold. I like Leupold scopes, but I think they're way overpriced. I have a couple, but they were purchased used. A lot of guys tout Leupold's resale value and their warranty, both of which don't mean didly to me. If they're as good as people claim, warranty shouldn't be a concern, and unless you're buying a scope for the sole purpose of making a few bucks, who cares about resale?
Good luck.