For me, poster paint. We're taught art (well, okay,- given crayons, pencils, paints, etc) here from nursery school until art becomes an elective in year 10.
After poster paint, oil. I only started using acrylics a couple of years ago when somebody gave me an "artist's acrylic kit" as a present and kick-started me painting and drawing again.
Da Vinci, if the brand name means anything to you. I think the kit probably cost about £5 for 12 colours, and I've upgraded each colour as I ran out.
Same with oils. My stepson gave me a "kit" of Bowmere oils that I'm upgrading as I run out.
I have a pretty expensive set of watercolours that I haven't even opened. Not because I dislike watercolours, but because I'd rather learn with cheapo stuff and start on the more expensive once I have a grip of the basics.
Maybe it's the Calvinist in me.....
Everything except poster paint and watercolour is now my favourite paint.
I just wondered which medium "hooked" you into art?