what is a good deal?

I've been testing a deal-verification system today and something surprised me.

I submitted a 3-pack of bug spray that Amazon showed marked down from $29 to $24. It looked like a perfectly legitimate deal.

The AI rejected it.

Why? It found the same 3-pack at Walmart for around $20.

I've had about 10 submissions rejected today for different reasons — shortened URLs, questionable reference prices, better prices elsewhere, shipping wiping out the savings, etc.

It got me thinking that most deal sites are really showing us discounts, which isn't necessarily the same thing as showing us deals.

When you're shopping online, what makes something a real deal to you?

Is it a certain percentage off? Lowest price across stores? Historical price? Shipping included? Something else?