They are 10x15 cm (4x6 inches) approx and the drawing you get will be chosen at random.
You can subscribe through Minds.com (a Social Network that allows subscriptions with usd and crypto) for 20$ (shipping included) or 16 Minds Tokens.
This listing gets you a drawing for 1 month (one drawing)
You can see many examples at the photo! Those were the Christmas ones.
The price includes standard shipping worldwide.