The best plastic backed adult diapers to buy and wear are the adult baby diapers from ABU.
ABU sells many good quality thick plastic backed diapers with some having cute prints such as the Super Dry Kids Diapers which are a Pampers Replica Diaper.
Then they have ABU Preschool diapers as well as ABU Simple diapers.
Northshore.com also sells some good quality thick plastic backed or poly backed adult diapers such as the Northshore Supreme Diapers.
Plastic backed adult diapers are the best adult diapers around as the plastic holds up better and they feel much better as well.
You can also buy attends poly backed diapers from websites such as Healthykin for around $30.00 for 96 diapers which are pretty good for the price.