Advertising on the internet is great, but sometimes expensive even with a budget. What percentage of your income should be set for online advertising?
You really need to get traffic for website – so I'd say 5-10% or even more would be ok. If it brings in a good rate of investment (ROI) then more, for sure. With pay per click its very easy to work out what you're paying and what its bringing in profits.
Afterall you don't advertise just because you think you ought to, there's got to be a payoff.