If it is what you want you should totally do it!
First things first...
Don't let people make you feel bad about doing it.
So many people think that sororities are just a bunch of girls who like to party, who don't want to do anything and are lazy. But on the contrary, that is the complete opposite of what they are. A sorority is a group of girls that share the same values and want to help the community and make a difference. Yes, they party and go out on the weekends, but everyone does so it shouldn't matter that they do it, because they still are accomplishing so much on the days they aren't partying.
Most people will be confused as to why you want to "pay" for friends!
But jokes on them, you aren't paying to have friends, all the money that is given to the sorority is to pay for so many things. Recruitment doesn't come cheap, nor does it come free. There is also the fact that most sororities have houses and there has to be upkeep on them, as well as paying for the utilities. There are the events that get put on by the sororities as well that aren't cheap, like formal or any philanthropic event. You aren't paying for friends, you are paying to be able to help with the activities and important bills that have to be taken care of.
So to any incoming freshman or any current college girl that is thinking about joining but isn't sure, you should do it!
Don't let people make you feel bad for wanting to do it! Don't let them tell you "well, that's a waste of time" or "that's stupid." They aren't doing it, you are! Let them judge you, but don't let them stop you from doing what you want! If you have the means and they want, and you have really thought your decision through and you know you want to do it for the right reasons, then do it!
You can tell everyone is negative about your decision to go and shove it!