This thread has been moved to the BP Discussion forum.
Have you been keeping BP? The care/husbandry isn't particularly difficult, but they do sometimes have some quirks...and it pays to have some experience with any species under your belt before trying to breed it. For example, I don't recommend that people breed if they have no experience getting babies of that species to feed (starting them - not buying an established baby). Have you dealt with nonfeeding snakes before?
Once you decide you are ready, you need to figure out what your goals are...and what your budget is. Don't buy something you don't like, just because its all you can afford...because you won't be happy when you have 6 babies that you can't sell quickly. If you like normals, and are ok with knowing you might have trouble selling the babies (especially the males), then that is the cheapest way in. You sound like you want to jump right to breeding, but there's something to be said for buying younger animals & growing them yourself (for one thing, it's less expensive

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If you have a little more money, and you like one of the dominant or codominant traits, you can usually get a breedable normal female, and a small morph male for a fairly reasonable price. If you like recessive morphs, you can pick up yearling female het, and a young male (het, or visual, depending on your budget). Expensive is a very relative term, and it means different things to different people. To some, a $250 baby albino is beyond what they are willing/able to pay for a snake...while others might be prepared to drop $3000 (or more) for a combination morph that will give a boost to their projects.
You mentioned buying a gravid...I thought your goal was to breed BPs?