Wes Bentley, the dude who became quasi-famous for calling a plastic bag "beautiful," is seriously in the hole with American Express -- and now they're suing him for over $90,000.

According to the suit, Bentley opened a Gold Account with AmEX, charged up $92,738.86, then never paid it off.

The card company wants their damn money back -- plus reimbursement for interest, attorney's fees and other costs.

The one word that's turning Ed McMahon from baller to beggar: Plastic.

Our sources tell us Pamela McMahon, Ed's wife of 16 years, is literally spending him onto the street. We hear she's completely "oblivious" to the late night legend's cash troubles, and shops like their life depended on it. Her AmEx bill is legendary -- the couple reportedly owes them nearly $750K.

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