J. CREW is a simplistic, preppy, New England-style clothing brand worn usually by middle to upper-middle class young people who desire classic, comfortable clothing. They do not make flashy clothing with big logos branded on the chest. Instead, their clothing is relatively understated despite somewhat high retail price tags.
"That was a pretty cool argyle sweater he/she was wearing."
"It was probably from J.CREW. He/She is such a prep."