When you meet with the advisor please ask about incidental fees that can be associated with being in a sorority. The fees that come to mind are the small things like t-shirt's that are required for certain events, secret-santa gifts, etc.. I know what it is like to be a broke college kid, where $20.00 is a lot of money and hard to come by. There were times when I felt very bad when I couldn't afford the t-shirt, picture, or gift. Having said that, I managed to scrape by and it was well worth it. Good luck to you!

It's been a while since I gave an update, so I'll wrap up this 'lil drama right here...
Yes, I understand that I did an underhanded thing by not telling my parents. It was really hard for me and I felt bad about it, but I knew I didn't want to tell them because I really didn't want to be influenced by people who didn't know much about the Greek system. I think my parents and I are on the same page now (they even gave me some money for my birthday to help out with dues--YAY!) so everything on that front is fine.
A couple days ago, I had an epiphany: it wasn't the amount of money that bothered me, because after some number-crunching, I figured out I'd come out okay. I just really needed to do some soul-searching to figure out if this was what I really wanted to commit to, both financially and time-wise. Quite honestly, I think I've been discouraged because I haven't been up at the house much lately. We got back from our fall break last Wednesday and not much has gone on before or after then because it's midterm time! I talked to my friend today (she is also in my sorority) and she said basically the same thing--that all I'd gotten so far is the alcohol education convocation we'd had to attend a week ago.
But anyway...I'm going to study tables tomorrow and new member education/dinner on Monday, and I'm very excited about that! I am glad everything has worked out okay, and I just want to thank everyone for the helpful advice. I have really appreciated it :)