Yeah, it depends on your post code. To get an idea try either of these two comparison sites
http://www.moneysupermarket.com/util...quiry.aspx?p=0 or
http://www.simplyswitch.com/?campaig...tricity+prices
You can get an idea of who is the cheapest provider for your region and you can compare other household bills as well....I think you can switch over online too.