I have been using low energy bulbs since 1991
I buy mine online (as I do
everything)
Here is a chart from one supplier I have bought from which shows how much cash you can save by using them
http://www.lamps2udirect.com/pages/calculator.php
And at this site
http://www.ebulbshop.com/
you can see what a wide range of shapes and sizes are produced nowadays
British Gas sound like they are giving away the older type which nobody will buy anymore.