Walmart’s prices are always based on how much they buy it for, then can be reduced as either a) better deals are negotiated, or b) they want to get rid of an underperforming product.
It’ll take a while for the price drop in oil to get registered in shelf products.
And a little FYI, price gouging is raising the prices of essential products and services during a disaster from prior to the disaster levels. They haven’t raised the price and I think you’d find it really hard to assert it is an essential product.
Probably won’t go down though with the lower price of oil since we’re staying at home so much.
Of course a percentage of the cost is in the additive package.
Maybe an expert on here can comment how much?