Unless you have to have the pristine sound of new strings, having a lot of guitars doesn’t necessarily mean that you need to spend more on strings. If you spend, say, 10 hours a week playing 1 guitar, you’ll end up with just as much wear as playing 10 guitars for an hour each.

Also, be careful of “cheap” strings - there are fakes out there. D’addario even has a web page where you can check the bar codes!