07/11/2012 at 06:00 AM EDT
was able to find what she was looking for during a recent shopping outing, but not with ease.
The singing superstar stopped by Alisa Michelle jewelry boutique in Studio City, Calif., on Friday, where an onlooker tells PEOPLE she "looked uncomfortable," walking around the store on crutches with a sprained ankle.
Despite her apparent discomfort, Clarkson was far from a diva, refusing to let the people working in the store close it down for her while she browsed.
"She was very nice and respectful, and she turned down a discount," the source says of the Duets
star, who purchased some custom pieces at the DIY bar, where customers can string their own jewelry with a variety of charms and chains, along with some necklaces and a cuff bracelet.
Clarkson, who stopped by with a female pal, wasn't the only celebrity to recently pop into the swanky establishment. Pretty Little Liars
star Lucy Hale came in the next day and also bought some pieces from the DIY bar. – Dahvi Shira