When DH and I decided I should stay home we did so because it made financial sense. I was taking home about $3600 a month. I was spending $2000 a month on child care, $400 a month on fuel to get to and from daycare & work, $800 a month for the maid because I didn't have time to clean house. After you factor in a couple lunches or coffees a week I pretty much worked to pay for working.
So how much would it cost you to work?