tldr; solved my own problem
I was having problems keeping up with all the new vinyl releases that were coming up so I built a tool to collate them into one easy to navigate place. A couple of years later this turned into a customer-facing website.
Then I realised that once I found the record I wanted it was hard to find a store that had it in stock as most of the records i wanted were very limited releases. So i extended the site to do a real-time stock check of my favourite record stores to show me which had the records in stock.
I now have record shops coming to me wishing to be listed in the stock check feature and I charge them money to appear, either through a monthly subscription or a CPA basis.