A question which everyone would like an answer for is whether their credit score is good enough or do they need to get it raised higher for better bargains.

A credit score, whatever it might be, is never enough. You would need to have a much bigger satisfactory loan at a lowest APR possible. So the question is whether you need the amount now or you need to have it in next 6 months. If it is next six months that you are looking for then it is very much possible to raise and have a credit score which would get you best deal at APR. 

If you need to have the loan right now, then I would say a score of 600 is not good. You would end up paying considerably higher amount as interest. 

If you were to buy an SUV then the APR typically would be 12% for you as compared to 3 % for someone with a credit score of 700+. 

If we were to consider a payment time of 6 years then you would end up paying almost 6800 more than a person with 700+ over the life of the loan. 

Moreover, the Car dealer would ask you for upfront down payment much higher than what he would ask from the 700+ scored person. 

So you would lose another $1000 in the whole process based on time value of that money.  

Now the question is how to improve upon your score. There is no short cut and even if it is present it is illegal as you would get caught one way or the other as the FICO algorithm is made sensitive to all the tricks made by all the credit repair scam companies. 

A score of 660+ is decent if you are looking for buying a car but a score of 720+ is what you should have if you are dealing with a mortgage loan. A mortgage loan is something you tend to take on your house and its length of payment is over 30 years. 

Now the obvious question is how long it takes to get over 720 from 600. It all depends on the number of negative items on your credit score combined with how much are you able to settle for paying for deletion of a negative from your credit score. In case there is something wrongly mentioned on your credit score, it is an added bonus since you have to ask for Debt Verification from the concerned credit card company or the credit agency. 

Time period would be roughly 5-7 months if you did everything right and made an all concentrated effort for increasing your credit score. So if you want to increase your credit score you should start at least 6 months before the actual purchase.