I enjoy these type of challenges and I think you may surprise yourself with what is possible.
The trick is that every time you face a decision, where you need to sacrifice one priority for another, you always pick the priority that makes you money faster.
This is a very good constraint for an early business to have.
I would recommend the SEO market as a place to start (speaking from experience). The top forums have very active marketplaces where people are already paying money for SEO services and software. The engineering behind the products is not generally good, and many products are snake-oil. You can differentiate yourself with a product backed by quality engineering, targeting a use-case that does not directly spam the web.
Think something like rank trackers. Tons of those exist, none are very good. The "moral argument" against rank trackers is basically nil, especially compared to the moral argument against blackhat SEO services. Therefore it makes sense to enter the SEO market with a product relatively benign, like a rank tracker, instead of something like a link spammer.
Go to the SEO forums. Find what people are paying the most for. Make a better product. Sell it.