Where can I get a bag to transport a 27 inch imac?
Like this
http://www.amazon.co.uk/iMac-27-Carry-Bag-Shoulder/dp/B007DEZ33U
but not as expensive.
Thanks.

I doubt you could find something cheaper thats designed to fit – but for not much more you could get a proper flight case.

The boxes iMacs are sold in are pretty good, maybe see if the box would then fit inside a bike bag

Unfortunately I do not have the box.
Maybe someone here wants to sell me one?

Job Done.

I do believe that the stand clips off on the 27″. If it does, you’ll find your options improve as it’s not so wide. I bought a £100 Samsonite hard-case suitcase for carrying my 21.5″ – it’s been on several flights and ferries, though I presume from your original want that you might not need that level of protection.