Britney Spears has been indulging in a little retail therapy reports MSNBC.

The “Oops, I Did It Again� singer celebrated dropping down to a size 6 by dropping nearly $10,000 on hot clothes in one hour at Barneys in Beverly Hills, according to In Touch Weekly.

Spears specified sexy yet casual clothes — but no tracksuits, a staple of her post-pregnancy wardrobe, according to ITW, which reports that Spears loaded up on soft, clingy cashmere sweaters.

Meanwhile, Britney Spears was nowhere to be seen when her husband took the stage last night at the West Hollywood Carnival, Brit was spotted rocking out by herself at an AOL Music party celebrating Federline's album release later that evening reports TMZ

The pop princess wore a pretty simple outfit to the party, consisting of a bright pink wig and big white sunglasses. We're happy that Brit got into the Halloween spirit, but you'd think a multi-millionaire like her would throw together a better costume.