You need either an e-product (e-book, course, membership site with private forums, etc.) or a real product (your consulting time $400/h, a quality product you buy wholesale (from distributer here or from factory via Alibaba) and sell via FBA (Fulfilled By Amazon) through a sales page on your site. (no inventory at your home). You can also generate affiliate sales revenue through product demos, videos, recommendations and a "resources" page on your site, which are affiliate links.