"Reasonable price" and "favorite" don't fit in the same catagory. The fact is, the better units cost an arm and a leg. BUT, you can get a decent unit for under $300, which is still high for simply calling coyotes, but the features of the higher end units have a purpose.
I'd look for a used FX3 or scorpion from FoxPro. Lots of used units on the market, and a guy should be able to pick one up for $250, if you shop around. The sound quality will be plenty good, and they will last ya a life time of calling. Most used units have very little use, and should be trouble free for you.