Bavarian Auto (bavauto.com) has nice mats for around $100. GG Bailey will make custom mats with contrasting stitching and serging for around $130. There is a company in Florida (dashcovers.com) that makes a decent set for under $80. I have a set of these for winter use. Will probably order a set from GG Bailey for my Cabrio. I do not recommend the MINI OEM carpet mats. Thin and they wear quickly. The rubber ones are nice and not a bad price.
I have both the carpet & rubber OEM MINI mats and both fit exceedingly well.
The carpet mats do tend to "ball up" like a sweater that is wearing where your feet are placed.
The rubber mats look great and stay put, although the driver's is a wee bit short at the top and so will not collect all drippings from your boots above the pedals. It's my first winter with the Cooper so I will monitor this and see if I need to supplement the driver's mat.