I convinced the teenager who mows my lawn to start spraying for bugs as a side gig to his lawn mowing gig. He now makes more money doing that than mowing lawns. Cost to start: $15. Makes $25 per visit. Takes about 30 minutes or less to spray the exterior of a house with off the shelf stuff. He is fully booked for the summer and does 4 clients a day (because he does not drive and uses a bicycle).