This is an interesting idea. Although there are many forms of the app already available, it doesn't mean your idea cannot surpass those and do things differently to create new markets. Facebook was not the first social media site for example.
I would suggest reading Blue Ocean Strategy, it's a great book when thinking about business ideas.
Monetisation is very important and there needs to be a detailed plan on how you monetise at different stages of the ideas growth. The local partnerships could work, but it would require a large business development team and would add costs, unless you're able to turn that into a win/win for independent retailers who would seek you out.
Do you have a business partner yet? That would be the first step in my view. These things take time and can be a long and challenging journey, find someone as crazy and passionate about the idea as you to keep you going.
Don't be afraid to chop and change the idea as you learn more and all the best of luck!
Blue Ocean Strategy seems very interesting. I'll start reading it shortly.
I don't have a business partner yet. I have not told many people about my business idea because I wanted to write everything down first. But I would feel more secure having a business partner. It will probably be someone who needs to be specialized into marketing or funding. Someone who has knowledge on how to get things done or has experience. Either way I'm not doing this without guidance.
I'm currently enrolled into a special business program. I will get personal coaching and I will need to attend workshops about creating a solid business plan, networking, pitching,...
Thank you for your effort and advice! (sending 2 shares)