Bargain cactus

Hey guys,

Thought I'd share my recent purchase.
Picked up this bad boy for $10 from ebay.
It was originally in straight potting mix and had a fern planted in with it (chalk and cheese I know)
So I repotted it into a nice free draining mix, dressed it up with some pebbles and chucked the fern into the ground.

Pretty sure I have established what it is but would be interested to hear your thoughts!

Most likely Parodia magnifica.

Excellent! That's exactly what I thought it was....
I seem to be getting the hang of this whole cactus thing! Lol