called in a yote on my first ever setup, but have a question

[HairoftheBear]

Ok so I have read umpteen articles on coyote hunting, went to Wal-mart and spent less than $50 for head to toe cam, got a hotdog call (I can make it yip, but not howl). I setup outside a noisy urban area and called in a yote to within 40 feet in 25 minutes. Lucky?...maybe so, but it made a believer out of me. I'm set on the rifle I want, but would like to know what kind of scope I should get. I'm moving to SW Idaho, where longer shots are more the norm. What should I expect to pay for a 40mm scope. A friend thought I should go up to a 50mm. Scope language is still pretty new for me. One friends said to to not pay more than a $100 for a scope. All I care about is to get the job done....killing coyotes....so don't need anything fancy, but I'm taking it seriously too. Don't want to pay hundreds of dollars for a scope, but then maybe I will have to depending what everyone here may be saying. Any recommendations or information on scopes in general will be appreciated.