| i use skype everyday for work and phone other skype users as well as landlines and mobiles, there is a cost for each call publised on their site, so far the only calls that have not worked out cheaper are to mobile phones in this country.
Call quality is often better than BT but sometimes is worse, I always start with it but have resorted to the landline for some important calls if it starts dodgy.
The Skype credit lasts for ages but if you dont use it all it does expire. | 
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