If you call a Toll free number of USA or UK from some other country, it will require you to pay International Call charges. However there are options available which allows you to make free calls to international toll free numbers.
Skype is providing one such service. Using Skype you can make free calls any Toll Free number of France, Poland, UK, USA and Taiwan from any part of the world. Skype will not ask you to have Skype Credits in your account before making the call.
Following is the complete list of Skype supported Toll Free codes –
France: +33 800, +33 805, +33 809
Poland: +48 800
UK: +44 500, +44 800, +44 808
USA: +1 800, +1 866, +1 877, +1 888
Taiwan: +886 80
Yakfree.com is also providing a Similar service, which allows you to make free calls to Toll Free numbers in USA and Canada.
Yakfree does not require you to install any software. It offers Flash based dialer on their website, which can be used to make calls directly from your browser.