Lindsay's Shopping Addiction

After snagging a pair of $1,240 Yves Saint Laurent platform boots from Barneys New York in Beverly Hills, Lindsay Lohan arrived at girlfriend Samantha Ronson’s  Hollywood home and threw away the bag and receipt.

Why?

“Lindsay doesn’t want Samantha to see evidence of her frivolous spending,” a pal of the couple tells OK!. “Samantha is pretty conservative with her money, so the fact that Lindsay never seems to look at prices stresses her out. Worse, Lindsay has resorted to hiding her spending from Samantha – not a good thing.”

Click here for OK!'s ultimate Lindsay Lohan gallery!

On the other hand, DJ Samantha earns at least $300,000 a month from her skills on the turntables.

“She is super responsible and takes her work very seriously,” says her pal. “She is never late for a gig and is fastidious about her bookkeeping.”

Lindsay’s only income as of late is the approximately $100,000 she earned from her appearances on Ugly Betty this season — before her publicist, manager, agent and lawyer take their cut.

 For her part, Lindsay’s rep tells OK!, “Lindsay works and makes her own money — she is allowed to shop.”

But Samantha’s friend tells a different story.

“Samantha loves Lindsay very much, but in recent months, Samantha has been very stressed about the responsibility she feels she has for Lindsay,” the pal explains to OK!. “Lindsay really needs to be honest with Samantha if she wants their relationship to stay on track.”

For more on how Lindsay's shopping is affecting her relationship with Sam, check out the new issue of OK!, on stands everywhere Thursday!