What were they thinking? (in General)

Some time back, I purchased a huge lesser tattoo at auction so cheap, even after paying 80k for reinking, and without any gain in the tattoo level, I could sell it to the store and still make a small profit.

Today, I bought a 4.9 mil NW Steel Familiar for 550k at auction; and its sell to store price is around 750k.

Isn't the rule like if you want to sell to make a profit, the least you can ensure is that the minimum bid price at auction is about 10 to 20 pc above the sell to store price?

not a rule at all... you just got lucky.

It takes a 4-year degree at a business school to understand that concept.