Single sections are usually significantly more than you might expect them to be. However, even if you just divide the rod's RRP by three (simplistic but not too far off the mark. Tip sections have an awful lot less carbon but an awful lot more rings), you've got a price of £56.66. Some manufacturers would charge an awful lot more than £70.
If you really want ouch, break a section of a pole. You soon realise how good value many pole packages are when you try to replace an individual section.