There are waiting lists and what not, right? So, apparently for some things there are people who want to pay and just don't get the chance.
It's not just that though, Alabama fans are not supposed to be going out there and paying recruits, so how can they help? They help by financially supporting the football team, that's what allows them to have a high paid coach, fancy facilities and so on. The only issue I'd have is if they start charging more than people are willing to pay, but that's not the case.
If people want free, there's events like A-Day, but then the complaints I hear are that "it's not a real game" and so on... yeah, well you can get your entire family in there for the low cost of free (including free parking), but it's only been full once I believe, so apparently expensive sells better than free anyway.