Let's say I have a startup web-app (e.g. ticketing system) ready to go live. I am planning to sell a monthly membership. I don't want to market/promote it, so I'd like to find a company to do that for me in exchange for a percentage of sales.
How can I go about finding such a company? I know companies like that must exist, but I don't know how to find them. I'm looking for advice on the discovery process.