How to Check/fix My Credit?

I recently tried to buy a used car for $5,000 from a dealership with no luck, even with a co-signer… MANY co-signers, a trade-in worth $1,500 and even $2,000 down…. with no luck.

I have a job, get money for school, and have parents willing to help me out (I'm sure they're sick of hearing about my car repairs from the 99 Dodge Durango I drive; 134,000 miles on it.) But am still stuck having to drive my junker around or finance through auto salesman I'm iffy about trusting with my money (my old junker is in better shape than the cars they're trying to force me into.)

My family has bad credit, and I've been told mine is limited.

I know I have an unpaid medical bill on my credit that may be spoiling things. I've smartened up with age (I'm 20 now), and I tried to pay that medical bill, but it has gone through two collection agencies and I can't seem to track them down.. *I know I can pay this off easy, as the collection agency most likely only paid half what I originally owed the hospital, but I have no other way than looking at my credit report to resolve this.

I'm determined to care for my credit now, but how?

Suggestion:

Pull your credit report at https://annualcreditreport.com (you can get one free report per year, make sure you get the report that includes all three credit bureaus). From that, you can determine who is reporting the negatives, get them paid off and give it time. It can take as little as a month to make your credit score take a nosedive. It can take years after to get it back to the "good" category.

After you get your debts repaid, go to the nearest credit union and apply for a secured credit card. More info on one credit union's secured card here: http://www.mctfcu.org/mct/credit_cards/visa_secured/ Most all credit union secured cards are the same or similar and operate under the same principle (this is a card secured by a savings account you open which is not touched unless you make a late payment or default…you pay it just like a regular credit card). Credit union secured cards often have no annual fees and lower interest rates than those offered by banks and after a couple of years of good payment history, they may convert your card to unsecured with a higher credit limit. Then give it time. With responsible account management, you can probably get up in the fair to good range on your FICO and qualify for an auto loan. (Another plus about going to a credit union is that they are usually much more generous about granting auto loans to their customers who have demonstrated financial responsibility.)