Credit Score Different

Question: I checked my credit/score online and it was different when I went to a car dealership.?
I got my Credit Report and score from all 3 bureaus online and went to a car dealership and tried to tell my score was alot lower. ( It was 549 online and 484 @ the dealership!!!!) I asked numerous questions about why it would be so low. I was furious about this. Does anyone know why this would be? Why doesn't it show on my report that I've paid some debts off and that I currently make monthly payments on some?
Answer: Did they pull a score from FICO?
www.myfico.com
Your Credit Score will be different with each of the 3 bureaus and fico. It is an always changing thing.
Renting Out Your Credit Score