Moss Room, Danish lifestyle and home themed site recommends Szputnyik shop to vintage-lovers visiting Budapest:
"It's another popular vintage shop in Budapest, however, it consists exclusively of clothes. Prices are around 100 Danish kroner (around 13 Euros) for example, vintage dresses. There are actually two whole shops in town. One is located at: Dohany utca 20, which is open from 10: 00-20: 00 Mon-Sat. The second is on: Király utca 22, which is open from 11: 00-21: 00 Mon-Sat"
Article: Julie Marie
http://mossroom.dk/2016/04/15/shopping-guide-til-budapest/