Key in my Saturn ION won't turn all the way

What is your question?

Just a few weeks after I bought my 2003 Saturn ION, we started having trouble getting the key to turn all the way to start the car. Sometimes we have to sit there for 30 minutes jangling the key in the ignition. I guess my question is, is there a quick fix to this? If not, what needs replaced? & how much would it cost? Thanks guys!