Is charging clients to run their Adwords campaign by using a percentage of their budget a good idea? What is a good percent to charge? Can a person learn quickly how to run an effective Adwords campaign or is there a large learning curve and a lot of experience required?
I have seen people charge 10-20% of spend for accounts spending 1-5k a month. As the spend increases you usually make less of a percentage. More experienced users can charge by the hour. The hardest challenge is not running campaigns, but building campaigns that will run well. I would suggest looking for a boss/mentor to learn from and help out on their accounts. If you are good with excel or other analysis tools you should be able to learn intermediate skills within a few months.