I am not sure if the supply or demand part of the equation is out of balance for sunscreen, but I just spent about $14 USD (170 MXN) for sunscreen at Walmart. There was no off-brand or generic versions available.
In the USA the cost is at most $7 USD (~90 MXN) while an off-brand version of double the size would be priced the same.
Why no love for the melanin challenged? Is this a variation on Montezuma’s Revenge?