A FSBO is a home where the owner is selling the house rather than using the service of a Realtor. It would be incorrect to assume that a FSBO (For Sale By Owner) house will be any easier or cheaper to buy than one listed by a Realtor, and often they can be harder and more expensive since you are dealing with an owner who is selling their own house. Do you think they have an interest in getting THE MOST MONEY ? Yes. Are they telling you the whole story? Are they required to work in your best interest, as your buyer agent would have to? No. Would you have to pay a Realtor to work for you to find a home? No. Are there many FSBO homes to choose from? No.
Are you sure you are not talking about a rent-to-buy home are you? These you rent but pay the landlord the normal rent plus an extra amount each month to go towards purchasing the house in a year. With poor credit these are going to just be a waste of your money since you likely might not be able to qualify for a loan in a year and if not you can loose that extra money you paid the landlord. Best to rent, save and improve credit - then buy.