The good spotting scopes start with the low end Kowas at about $400. I doubt you will find any good scope any cheaper. Don't forget that you really do need the 45 degree eyepiece, straight through scopes are the pits after a while.
The only cheap scope I thought had acceptable resolution and a 45 degree eyepiece was a Pentax reflector. I bought one 15 years ago for less than $200 and still like it. I have no idea if it is still in production or what the price might be now.
Jack