There are three ways to use Shopify effectively to add profits to your home based or local service business.
1. Design and sell themes
2. Design and sell apps
3. Sell your inventory using their eCommerce platforms.
The first two make a great add-on for a local business marketing and web development company.
The third is great for anyone with a home-based-business or a commercial physical location. You can have people prepay online and then come pickup or include a local delivery service. Whatever service that will give you more visibility over your competitor. Even if you already have a website, putting your inventory online for sale will encourage your local community to buy from you. If you choose to start selling nationally you can do that as well. An online checkout merchant account is very versatile.