I have been using a mailbox at a private mail store as my address for years now without issue.
There are lots of unskilled jobs out there such as the ones mentioned above. Those are great for small amounts of low-stress pay. A long term solution for better pay would be to pick up some sort of skill that is regularly needed on a short term basis. Pay can be quite good and you get to choose when and where you work. You may have to pay for a class but it will pay for itself quickly. Construction-related jobs can be good for this. Carpentry, equipment operators, electrician, etc. I met one guy who works on gutters. When a big storm hits he drives to that town and goes door to door offering to repair gutters and clear debris. I work as a poker dealer for big tournaments, there is a post in Bob's blog about that.