I agree with booondocker, the dealership that is selling them may be your best avenue.
But when you say your credit is bad , there is a series of calculations that go into your number or credit score. Do you know your score ? 2 important factors are for lack of better words fixed debt & revolving debt and then there is your debt to income ratio or percentage. There are 3 main credit agencies that formulate " your score ", you will have a specific number of businesses reporting " good " on time payments or " bad " payments which are late, beyond the 15 or 30 grace period or " WORSE YET " a default judgement against you. THEN To get a loan you have to be able to show that you have the means to repay the loan. Before you get all fired up about buying or loosing the opportunity to buy the sleds you can go on-line and get your credit report for free, then sign up for their fee to get access to your scores. The best way is to sign up , then cancell in the 9 day grace period and they only will charge you $1. ( for your scores ). Review where you are at. You may have to eat some " Humble Pie ". Money is tough to come buy nowadays. My wife & I just did a 3.5 % re-fi ( because we could ) some folks are upside down in their houses and they can't. Never the less since we made prudent moves with money we got the lending agencies at our door. There is a time & place for everything. Rember " CASH IS KING ".
You might have to start over and rebuild your credit, it is a slow process, but knowing how the credit agencies work and how scores are calculated will help.