[zapstar]

For me, https://unitprice.org and https://okaycup.com — These track prices on Amazon for certain sets of products and finds the best price per unit, which isn’t always the largest quantity item. Revenue is all from affiliate links.

Edit: Oh, you said $500, not $5. Oops!

[zapstar]

Update: I made $6 yesterday because someone bought 1,200 bouncy balls.

[ramphastidae]

I’ve always wished for something like unitprice.org. Well done!

[zapstar]

Thanks for the kind words! Let me know if there’s any product you want me to add!