Shared cost numbers are premium numbers in the UK, Australia, Germany, Switzerland, France, Portugal and the Netherlands, often used by businesses and other institutions. They are charged at a higher rate than regular numbers.
Shared cost numbers have area codes 0843, 0844, 0845, 0870, 0871, 0872 (UK and Switzerland); 0180x (x representing a series of digits [France and Germany]); 808 (Portugal and International); 13xxx (Australia); and 088 (Netherlands).
Calls to shared cost numbers are not included in any of Skype's subscriptions; you'll need some Skype Credit to pay for them.
Check the price of shared cost calls.