As much as you want it to, essentially. You can set your own AdWords budget, depending on your overall marketing budget. You can spend as little as a few hundred dollars a month; the minimum to get started with AdWords Express is a rather absurdly low $50.

There are a few things to keep in mind when determining how much to spend on AdWords:

  • There may be a tipping point that you have to cross in order to turn a profit. Sometimes you have to spend more to get more.
  • If you want to hire someone to manage your pay per click campaigns, you’ll have to spend enough to justify that cost. It doesn’t make sense to hire a PPC manager at $50K a year if you’re only spending a thousand dollars a month on PPC, obviously.
  • There’s no reason to arbitrarily cap spend on profitable campaigns. If you create some test campaigns and find that you’re getting ROI from PPC, you might as well spend more to make more.