I think the first time around they were included with the free shirt they sent out. Second time they were with the free socks. Maybe general merch store orders might include them too.

For some reason I never received any stickers, shirts, or socks here in France.

I do remember them asking about shipping information at some point though.

They sent out emails where you had to put in the order, IIRC $5 shipping so not entirely free. Maybe it was limited to early subscribers or something.