At the beginning of each week, I print one for each of the kids and stick it to their bedroom doors. At the end of each day, we go through the house and examine the rooms. If the room is clear of their things, they get credit for that room for that day. At the end of the week, if they have at least 30 stickers, then they get $2.50 for the week. They get paid in quarters - 10% ($.25) goes into a savings jar, 10% goes into a giving jar and the remaining 80% ($2.00) goes into their ATM machines to use for spending money, or whatever they want to do with it.
I have to say that so far I have actually been pretty surprised at how effective this simple little concept has been. The amount of cleaning that I have had to do on behalf of my children has significantly decreased in the past 3 weeks. Plus, the upside is that they are learning to tithe & to save.
(Credits: I used "Make Chores Fun" by Kate Hadfield & Jacque Larsen to make this chart.)