There is a lot of work involved to properly installing a sump pump. You can send this video to a customers to show them how much work it takes. After seeing it, they'll decide that getting water out of their basement is probably not a DIY project.
You might want to point out to them that in this video there happened to be an outlet box right next to where we installed the pump, but that might not be the case in their home, which means they might need an electrician to come in and do some wiring. Also, in the house in the video, it was relatively simple to run the drain line outside the building.
And before you think that you can just run a drain line into a municipal storm drain, check with your town. Most locales won't allow this.