The correct answer is B, "Having bought."

We need a past participle that associates with a completed action. Out of the given options, "Having bought" is the only one that fits this requirement.

A. "Having to buy" doesn't work because it implies a present participle (having + verb-ing) and indicates an ongoing action, which doesn't fit within the sentence's context.

C. "Having been bought" is another past participle form, but it implies passivity. It means that something was bought for the subject, which doesn't fit the context since the sentence doesn't mention anyone else buying anything.

D. "Having being bought" is grammatically incorrect as "being" should not follow "Having."

E. "Having buy" is also incorrect usage as the verb "buy" is not in the past participle form.