Stick with brand name chains and you'll be fine. The big difference in price (once you get away from cheap department store or off brands) is in weight and finish. Shimano, SRAM, KMC, I've used them all over the years with about equal results. If you are looking to save bucks, go with the unplated, solid pin chains. They work fine and are plenty durable if you don't mind sacrificing a few grams and are vigilant about keeping your chain properly lubricated. There is really no purpose in putting a high-end chain on a mid-level bike and groupset.

Yep, you are about right. $20+ is where quality chains for 9sp and up start.

If you are really strapped for bucks, a bargain chain will get you by, but they don't save money in the long run compared to an entry level chain from a quality manufacturer. Your best savings is in proper maintenance and adjustment to maximize the life of a good chain.