Essentially, as much as you want it to. Some will quote you thousands to tens of thousands a month. That is really how much they hope to commit you to spend with NO real justification [ to put it nicely ]. No one, could realistically give you a quote in advance, without knowing a lot of information about your business, location, competition, market, product and/or services you offer, etc. And even then, that would be at best an estimate. On the other hand, if really justified, you can create some test campaigns, spend a few hundred dollars for a few months, and if you find that you’re getting a good return on your investment from your PPC Campaign investment [ for each 1$ on advertising you should get at least 10$ in sales ], you might as well spend more to make more.