This is a fun outside activity for kids to do in the summer. I take spray bottles (either from household products that are empty or inexpensive ones from the dollar store or similar) and fill them with a small amount of paint and mostly water. Don't use too much paint or it will clog the sprayer. Shake it up really good and you have spray paint.
I get the ends of the rolls that our local newspaper can't use, which they sell for like $1-$2 and it really has a lot on it. Tear off a long piece, attach to a clothesline, fence, etc., and let the kids create a masterpiece with their spray paint. This can later be used for gift wrap. Another option is to use old bed sheets. Kids can create their own unique sheets for their bed! It is a lot of fun!
Note: I also use the end of the newspaper rolls for other things such as packaging items for moving or mailing, and covering the table before craft time. Check it out to see if you local newspaper offers this service.