Most music stores are recorder shops of sorts. Cheap plastic recorders are usually there, sometimes the better quality Yamaha and Aulos plastic models.
For higher quality recorders you generally have to shop online, unless you live in places like London or Boston. There very few specialist recorder shops, the main ones are listed below. Most are staffed by recorder experts, a call to discuss what model to get is time well spent. They will also have good advice on recorder teachers, maintenance, workshops and other recorder matters.