Depending on the private college it may not be any more expensive if they have generous need based scholarships and grants.
Have you already figured out your
estimated financial aid contribution? That will help you gauge what kind of need based gift aid you qualify for. In addition to any private scholarships, grants and loans you apply for.
One of the things that has been mentioned here is to begin with the end in mind. Can you identify what it is you're looking to get out of your education? Are you going for a particular major, for strong connections, for a particular learning environment, what kind of student body do you want to be a part of?
I did my undergrad at an expensive private college --38k a year. However, they gave me a need based scholarship and it ended up being cheaper than attending any of my state school options. It fit exactly what I was looking to get out of education and open the door to my longer term goals.
There are plenty of
financial aid calculators that will help you get an idea of what you will owe after you graduate with a particular starting salary. But those are guidelines. Keep in mind that federal loans are always better than private loans (in interest rates, repayment plans, life of the loans).
Good Luck!!