A BEL can be had for $400 or sometimes less (have seen them for $350)... That is a lot less than the cost of feeding a male to breed with your snake, then buying an incubator, a baby rack, and feeders for all of the clutch until they sell. I'd just buy what you want. You would probably end up spending about 3x that much in the end. Keep in mind that you can have medical issues with breeding as well. It is not unheard of for females to become egg-bound and need surgery or for males to be injured during breeding (prolapse), etc. Tack on some vet bills to the costs above and then your BEL just got really expensive.
I'd suggest saving up for the BEL, get a male, then years later, if you are still interested and can afford to invest in all the equipment, etc. then try breeding at that point.
In some areas, it can be hard to move snakes. If local sales are your only option, you could be waiting for a while. I would not offer animals for free on CL. They are often gotten by people that will not care for them properly or might even abuse them.