Very nice project! Can you tell us a little about your tech? How did you crawl Amazon's USB listings, did you use their API? And then how did you figure out if an item has the feature you are looking for: What was your parsing and extraction logic like? Finally, how often are you refreshing your index?
I'm always interested in projects that have a clear path to monetization.
In related news, I built a simple tool to track real estate. For e.g. in San Francisco prices are down by about 3% across all property types (Condos, Townhomes, etc) compared to 6 months ago:
You can very quickly get a snapshot of the latest price trends with just a few clicks for each of the 300+ cities in the Bay Area. Check it out - https://agentsunlocked.com/
So you'd be best served to Google for the contact lens of your choice and pay for whats the cheapest.
Note: When I tried to re-order from EZContacts, they were charging close to $50. So always start a new search when you are trying to order Contacts online!
https://www.econtalk.org/michael-munger-on-antitrust/