When you are working with an artist to create a marketing piece, the artist may have a couple different ways of charging. One way is he can charge you by the hour, (which in my opinion can get more expensive) or you can ask for a quote, for a specific job. Give the artist all of the details so they know approximately how long it would take them, and then they can give you a quote, with a certain amount of revisions.
This way, if you were quoted with 5 revisions, and you hit number 6, you know the price will go up and from there you can discuss with your artist how the price will change. Whats really important to recognize, is that you may think a piece may only take the artist 20 minutes, and think the price should be low, but you don’t actually know what the artwork entails. So if you have questions, ask. Make sure you know everything you need to know before moving on with any artist.
Make sure you like their work, and make sure you like their price. Don’t forget, your paying for it. So if you don’t like what they have done it is ok to tell them. Just be nice about it!