You can build your own Cobra for fairly "cheap." Most of the parts can be shipped to your home and you can assemble them, or you can go to an authorized dealer and they can set you up with a rolling chassis (complete interior, paint, etc.) for about $39,900 (£22,500)... You of course need to add your own Ford 289, 302, 351, or 427/428 and your choise of transmission. Personally, I would go for the Ford Racing 302ci V8 (345hp) that retails for about $3,400 and match that with the Ford Racing Tremec-5 5-speed manual transmission that goes for $1,700... So total cost (and its really rough here) is about $45,000 (£25,500)...
You can see that they do go into pretty good detail with the car.
The next best thing is the Superperformance Coupe, a replica of the Shelby Daytona Coupe.
Prices arent listed, but expect them to be a bit higher than a completed Cobra depending on engine choises.
The big news with replica sports cars is the new Superperformance GT40 replica that will be available later this year and will cost in the neighborhood of $80,00 to $90,000 (££45,300 to 51,000) when completed.