I don't have a maid, but I do have a cleaning lady that comes by once a week. One of the perks of living in Asia. You can get a cleaning lady for $15/week.
But no, I don't give any tips in money, but I guess I do tip. She gets all the empty bottles / cans, she gets used clothing, just a while ago I gave her a good sized toaster oven that I bought for around $200, and things like that.
Once she needed help, which I was happy to provide, because I trust her, and know she wouldn't ask unless she really needed it. Was only like $30 anyway, and is just what you do when you live in a Buddhist society.