That's the point...
...We are baffled as to why there is such a HUGE discrepancy in prices!
Be baffled no more... You can buy a bottle of water from a walmart for less than $1 or you can buy it from Disney for $3... the reason they charge 3 times the price? Because they can.
Unfortunately there are a lot of people that are willing to pay way over the average price and as long as there are enough of them Disney will continue to charge as much as they can. Your best way of avoiding the damage to your wallet is to buy stock in Disney so you'll be getting money from the over charges instead of losing it.