Katy Perry often pays for John Mayer's massages.

The American singers have been dating for several months, keeping things on the lowdown before going public with their love in December.

They have been spotted out and about enjoying dates, with Katy apparently happy to treat her beau when they are together.

"One time a street vendor approached them selling roses and John said he'd buy some for his lady, but when he reached into his pocket he didn't have any small bills," an insider told National Enquirer. "So Katy ended up paying for her own flowers! And she frequently picks up the tab for their gas, travel, expenses, dining - even his massages!"

Although John is happy for Katy to shares some expenses, there are others he draws the line at. The star has sparked speculation he is planning to propose after he was spotted looking at engagement rings over the Christmas holidays.

Katy apparently has no problem sharing the cost of things, with her family also happy with the arrangement.

"Maybe he's a saver and not a spender," her mom apparently said.

Katy, 28, and John, 35, began dating after Katy's divorce from Russell Brand last year. Their friends are said to be convinced their romance will go the distance as they are so right for each other.

"John is serious about Katy, that's for certain. He has never imagined settling down with someone, but he's infatuated with her. They have the same sense of humour, they love the same music and they love to travel together. And, of course, she's beautiful. Although John's got a reputation as a ladies' man all of their friends completely approve because he's so dedicated," an insider previously said.