Good and cold good date

Got to have it!

I don't understand why a gallon of Walmart Great Value Milk 2% Reduced Fat Gallon Plastic Jug sells for $2.25 but a gallon of Sam's Member's Mark 2% Reduced Fat Milk is $3.38, $1.13 or 50% more. I know Sam's doesn't match prices, but this is ridiculous, they come on the same truck from the same warehouse. Other than that they taste the same & have similar sell by dates.

Grayish appearance when opened no thanks