Matching girl/boy outfits

Cristina • First baby born in April 2016 👶🏼 Expecting baby #2 June 2018 💙
My friend has a daughter that's three months older than my son. I want to buy them outfits that match like one is pink and the other is blue,  ut I don't know where to find them. Does anyone have any ideas where I could find something like this?