Pay whatever it takes to get the job done and nothing more...
For example if you pay 20 bucks for a cheap holster but it doesn't hold your gun very well then you spent 20 bucks and the job isn't done, where as if you spend 70 bucks for a quality holster then the job is done but you don't have to spend 150 or more for a higher end holster. I use this principle for most things like range bags, ear muffs, reloading equipment.
I don't use this principle with guns though, because some can say that a Hi-point can get the job done. I find that taste, comfort, and that feeling you get when you see a really sweet gun in the case at your local gun shop is more than enough reason to splurge.
Hey.... it works for me...
Si vis pacem, paba bellum