ehh.. I never like being asked what my budget is. That always leads to being shown a product (whether a car, house, bike etc) that
coincidentally is right at the limit of the said budget. Isn't it a fortunate coincidence that the product that best suits me, is the product that just meets my budget...
A budget is what could be spent, not necessarily what I want to spend. On that note, I've heard the question before put as "how much do you want to spend?" to which I'll invariably answer along the lines of "want to spend? $1 sounds good"