Batik is the thing to buy in Pekalongan. Prices range from inexpensive stamped cloth to more costly hand-drawn batik tulis, and the difference is worth learning before you buy. The Batik Museum gives useful context before you start comparing pieces.
Kauman and Pesindon are good for small workshops and showrooms, while Pasar Grosir Setono is better for volume, ready-made clothing and lower prices. Bargaining is normal in market settings; in formal shops, prices may be fixed.