800 numbers are the free to phone number for companies and exist all over the world. From 1800, 866, 855 in the USA to 0800 numbers in the UK, Germany and Holland; it's a very popular number and very easy to obtain. City Numbers
recommend that these numbers are generally considered to be the fore front of customer promotion due to their cheap nature and recognised number throughout the world.
There are some costs for free to phone numbers across the world and this normally includes a monthly fee, a set-up fee and a pence per minute charge for the call divert. Some countries include a mobile surcharge in order to incorporate the costs from the callers mobile phone, making it free for them to call on a mobile phone, but costing you (the freephone owner) a little more per call.