Selling real flowers is where things can get tough. Many people already have a green thumb, and often they already supply flowers to friends and family. You will need to figure out which flowers will survive the shipping process, and decide how great of a distance you are willing to deliver across. Again, clear, attention-grabbing images will be key for successful selling.
I surprisingly get a lot of people asking to detail their car. I never intend to make a business of it, but I love doing it to my cars and people ask me to do it to theirs. All it takes is a cheap orbital buffer (mines a used craftsman) and a shop vac. I normally get easily $100 for a basic wash/wax/vac, or $200 to remove scratches and polish then wax the car.