Jennifer Lopez and Casper Smart
07/05/2012 at 06:00 AM EDT
In a group of about 15 people, Jennifer Lopez
, boyfriend Casper Smart
and X Factor
mentor L.A. Reid made their way into Blue & Cream's brand new boutique in East Hampton on Monday.
"They tried on sunglasses for over a half an hour," an onlooker tells PEOPLE, adding that they also checked out handbags and customized Havaianas. "Casper bought Jennifer a pair of the newest Brian Atwood stingray shoes and L.A. purchased his wife Erica a Tori Praver bathing suit."
Free from any security guards, the large group also headed across the street to the original Blue &Cream store, where Casper purchased some Oliver Peoples shades, and his lady love bought a pair from Stella McCartney.
"The [store] locked the doors for this shopping spree," the source says. "Onlookers sat outside and tried to get a glimpse of [Jennifer]." – Carlos Greer