It looks like the crack is 360 degrees, so probably a complete break. The bowl is in such bad shape that at this point it's hard to tell what's wrong with it. Even if the seller accepted a very low bid it would be pretty risky, I think. The only way I would do it is to make your payment be contingent on a restorer's/repairman's assessment that you would have something reasonably sturdy after his repair; but then you have to pay him! Better deals elsewhere, I think.