Is it bad manners to only buy 1 card of a connecting art set from a vendor? | tcgmode

I was at a card show earlier today and found a vendor selling the 30th anniversary Rowlet, Litten and Popplio cards, which have connecting artwork. I was only interested in Litten, and all the cards were priced individually, so I asked to grab just the one for his sticker price of $10 CAD. Righ...