This pattern should suit even beginners, and can be whipped up in less than an hour depending on your skill level.
As well as having clear written instructions, it also includes a picture tutorial.

The assumed knowledge is as follows:
Chain
Slip Stitch
Single Crochet
Half Double Crochet
Woking in Joined rounds
Basic Sewing
Stitching in Back Loops.

All stitches follow the US version, but there is also a UK Stitch conversion in the pattern!

They stand at 9 cm tall (with +1cm stretch) and have a base circumference of 25cm to 27cm

You are welcome to sell what you make, as long as the appropriate source is credited. More info inside pattern.