how do you know it's 80%? have you spoken with other local buyers? Maybe the floor is something like 20%?

let's say it is 80, can you imagine a way to get 80% of the supply (stores) onto this platform? Or, could you chart a path to get to x% supply after y weeks?

idea 1: fake it, just list stores and items on a website and find out a way to get users to see it without paying for ads

idea 2: sign stores up one by one, using some interview-derived value proposition, and get your friends to help onboarding new stores, challenge them to sign up x% more stores per week

idea 3: post about it on hn :(