I disagree that a scope should cost half as much as the rifle. If the rifle is a great deal (a used Husky 30-06 for $400), should someone put a cheapo scope on it? Vice versa; if a rifle is quite pricey (like a Sako 85 for $2000+) do you really need to spend over $1000 to get a scope that will fill your hunting needs?
My take on scopes is that you should pay enough to get a scope with good glass and a good warranty, regardless of the price of the rifle. In my opinion, that means a US or Japanese made scope. To save a few bucks you can forgoe resettable turrets, adjustable objectives, and fancy reticles. A basic but good quality 3-9x40 scope should run from $400 to $700. Or much higher if you want ultra-clear European glass but Swarovskis are way out of my budget. I'm partial to Leupold, myself, but I have a few Japanese-made Bushnells that are decent. I regret buying Chinese Simmons scopes for my rimfires because they are garbage.
Nikon and Burris also sell some good scopes. I say sell because most scope manufacturers don't own any factories. They contract out production to different suppliers based on the required quality for the specific product line. This applies to Vortex, Nikon, Bushnell, and lower end Burris scopes, among others. It's not bad thing: the Japanese optics factories can make excellent products. This is also why there is such a huge price and quality range in the different Vortex products. Chinese Crossfire, Filipino Diamondback, Filipino Viper, and Japanese Razor HD.