Britney Spears and Isaac Cohen appear to be hitting it off.

We've talked a lot about that in recent days. But what about FedEx?

Britney's estranged husband, Kevin Federline, is reportedly on such a tight budget since the pop star announced she was divorcing him that he's doing anything he can for dollar$.

Sources say he recently tried to return some clothing she bought for him in exchange for money, rather than store credit.

That's pathetic. But then again, he's been Playing With Fire all his life, so it's not shocking.

In late December, the former back-up dancer and current WWE star (sort of) reportedly tried to return nearly $15,000 worth of pricey Libertine and Mastermind Japan threads that now-former sugar mama Britney Spears purchased for him.

Apparently unable to sponge off Kendra Jade, Federline returned the items at exclusive Los Angeles store Maxfield, which included a jacket that cost $1,620.

The absentee father of Sean Preston and Jayden James Federline wanted a cash refund for the merchandise, which still had the original tags, but when the clerk refused, he settled on a store credit.

"He was looking for pocket money. Now he's going to try to sell the credit," a witness said.

Federline may not be going Tori Spelling on us just yet. He may have more cash soon, given his recurring pro wrestling role. And he is rumored to be appearing in a high-paying ad during the Super Bowl.