Yes.
Carpets can be purchased at TAP (Take away price) meaning you carry it home on your back or stick it in the boot of your car, cut it to the correct shape and size and lay it yourself.
Or
The shop will do it for you complete with felt, gripper and door strips if required.
That of course means of course 2 very different prices. You should discuss this with the shop before you purchase and decide which option is for you