Many businesses find a big increase in revenue when they introduce customers to a low-priced product, then step them up to increasingly more involved and expensive products or services. Customers are ready to spend more for more advanced services as they come to trust and rely on you. If you aren't able to provide extra products or services yourself, contract with others to provide them for you. You can easily offer your customers lots of products and services supplied by others at very little cost to your own company. Then Go Wide and Deep.
All businesses start out with some idea of what they want to sell.
In the beginning you develop a few promising products and services and put them out there to gage the public's interest. Some products work, others don't, and sometimes you get a request out of left field that turns into your most important profit source. When I started my business, I thought that handing out marketing advice would be my bread and butter. Before long, someone asked me to write a press release. Presto, a new profit source.