Where to start?

Hi all, thanks for reading this.

I've recently turned 30 and in the UK. Watching people via social media open packs recently and has brought back some nostalgia from a place I didn't know I had good memories from.

I 'used to' collect cards when I was younger, much like others, and wanting to build a little collection. Not looking to make money or hold PSA 10 insert card here, but a little collection for myself.

I personally prefer the older generations (1 through 4). I have seen the more recent 151 cards but not sure where to look; Facebook, vinted, card shops, shows?

Any help on this topic would be greatly appreciated, thanks again.