As per some people spot what they think is a market and are in for the kill.
Obviously person or persons found boxes of Oxydol cheaply (or they may even have fallen off a truck...), and think they've struck gold.
Am always amazed at those flogging detergent on fleaPay, Amazon or elsewhere for 2x, 3x or more price of what one would pay at shops.
Can find Tide liquid detergent at Target or Rite Aid often enough on sale for around $6/bottle. Even when not on special offer prices are rarely above $11 or so.
Some clever chops want to sell same jugs of Tide for $19 *plus* shipping.
At least with Amazon if your powder or detergent arrives damaged and or having leaked out, they will reimburse. Not so sure about fleaPay, CL or whatever.