RetailMenot - The RetailMeNot mobile app allows you to find deals on the go for both online shopping and in store shopping.
Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.
Slickdeals.net - Slickdeals: The Best Deals, Coupons & Discounts on everything
FriendlyData - Communicate with databases like a human
Honey - Honey is a browser extension that automatically finds and applies coupon codes at checkout with a single click.
SpreadsheetDB - A database that you can query with spreadsheets