A great part-time job that also happens to pay cash is working in landscaping. Most of the time, they will pay $100 a day or $15 an hour.
Do you know a couple looking to get out for the night and need a babysitter? If so, there is a great chance they will most likely pay you in cash!
You can help family, friends, or random people with their moving needs and charge $40 an hour or more for moving things.