Up for sale is my M3 (e92 though it may fit e90, not positive) car cover as I no longer have the car. It's a Covermate, semi-fitted Ultima edition, and is in overall great condition. Some light dirt on the exterior, but overall in excellent shape. Link
Retails for around $210 and I'm asking $110 including free shipping
anywhere in the states. I had initial hesitations around buying a semi-fitted cover, but I ended up being very happy with the product. Overall great fit, and absolutely no issues with excessive movement (can result in excessive scratches).