I always considered myself as "thrifty!" Cheap end scopes have cost me twice! I am not saying that you need a 500+ scope, and I still think that once you get past the 300-500 dollar range you start reaching a point of deminishing returns!
But having been burnt twice (one Tasco & one Simmons) I'd say get the best that you can afford and/or live with!!!!!
If you can accept a worse-than-average scope failure rate on a hunt, then cheap is OK.
When I consider having to re-buy a cheap scope twice, figure in the total costs of hunting (equipment, leases, travel, not to mention scouting, stand clearing, and other work) and don't forget, possible lost opportunity at a lifetime animal, a little more spent on a better scope could just be a bargain!