By Frank Pingue

TORONTO (Reuters) - China's Li Na is tipped to become the richest woman in sports but the French Open champion has yet to venture on a shopping spree and prefers using her husband's credit card rather than spending her money.

The 29-year-old world number six, who has many companies battling to cash in on her enormous popularity in China, seems to be in no rush to dip into her cash windfall.

"I still like to use my husband's credit card because I want to save my money," Li joked with reporters this week at the Toronto Cup where she is the sixth seed.

"But right now I am always busy doing many things for the sponsors and I do not have time to enjoy shopping. So maybe at the end of the year I will find time."

Li was ranked eighth on a recent Forbes list of top earning female athletes but is expected to charge up the rankings and challenge Maria Sharapova for top spot after her breakthrough win at the French Open in June.

Li took several weeks off since her shock second-round loss at Wimbledon in June but returns to action on Wednesday where she will face either compatriot Peng Shuai or Spain's Lourdes Dominguez Lino in the second round.

Regardless of her performance in Canada, it appears Li may need some more time comprehending just how big a deal she is in China following her breakthrough at Roland Garros.

"I was very surprised because I thought after Wimbledon, because I didn't do well in Wimbledon, that maybe I would go back (to China) and people would be like 'who is she?'," said Li. "But still ... a lot of people came just to see me and to say congratulations."

(Editing by Pritha Sarkar)