Selling baby diapers can be profitable.
Babies will always need diapers and parents are always buying disposable baby diapers as well as cloth diapers.
The disposable baby diapers are more profitable than selling cloth diapers but you can profit both ways.
I actually do profit some by going to places such as Costco, Sams Club etc and buying baby diapers such as Pampers, Huggies etc in bulk.
Then I go online and sell them on Amazon and through Ebay.
I can actually make between $10.00 to $20.00 profit on boxes of diapers.
For example if I paid $40.00 for a box of Pampers I could sell those diapers for $70.00 and make a profit even with shipping.
Some people who are well off financially don't care what they pay for the diapers and will buy them even if it's cheaper in store.
A diaper making business can also be profitable as well but you need money to buy the diaper making machines and a building to put it.
But diapers will always be in demand both diapers for babies and adult diapers as well.