Many times my career as a teacher accidentally seeps into my home life, and this is one of those cases! I decided to use a clip chart, like I do in my classroom. I separated it into 5 sections, and they start in the middle each day. They can move their clip up for doing what they're asked the first time we ask them, or for being particularly helpful. They move their clip down if they're not doing what we ask. If their clip is in the top 3 sections by the end of the day, they get a star. Five stars at the end of the week earns a dollar in allowance. Another dollar can be earned on Saturdays by doing Job Jars.
To make the clip chart, I cut 5 different sheets of scrapbook paper to 8.5"x 2.5" and then arranged them on a piece of cardstock, lightly gluing them down (not sure why my model is so resentful - I didn't actually want her in the picture anyway).
here if you want - sorry, cute font didn't make it over to Google Docs)
When they get the money for their allowance, they can either save up for something they want at the store, or buy something from our Prize Box, which is made up of toys I find on mega-clearance and the dollar bin (which I then mark up a little bit from what I paid, hee hee). So far, they've been loving it!