The worst hit are Scottish Power customers who may be charged up to 189 in one area more than customers living elsewhere, says uswitch.
The most expensive areas of all are Cardiff where online customers pay 949 a year on average, with Nottingham the cheapest, where the same customer is charged 855.
Scotland too can see big variation. An Edinburgh household could be penalised by a 40 regional penalty compared with an extra 104 paid in Aberdeen.
Ann Robinson, director of Consumer Policy at uswitch, says: "Regional pricing is a key part of the competitive battlefield – the important thing is for consumers to understand the postcode lottery and avoid becoming a casualty.
"They can do this by making sure they move to the most competitive plan with the most competitive supplier in their region. Even though all suppliers offer their cheapest prices online, these can vary by as much as 155 in one area, which is why it's so important for households to shop around."
Eruption of claims
Tens of thousands of travellers are still waiting for compensation after their flights were disrupted by the volcanic ash cloud in April.
EU rules state that European airlines must foot the bill for stranded passengers' hotel and food bills. However, most airlines have a huge backlog of claims to process, according to the Air Transport Users Council.
Of the 38,000 flights that were cancelled during the six-day shutdown in April, 4,200 belong to British Airways. The airline says it has been swamped by the sheer number of people claiming under the EU rules, and adds that the continuing industrial dispute with the cabin crew staff has affected its ability to process claims.
BA has appealed to claimants to bear with them while they clear the backlog. A spokeswoman said: "We have thousands and thousands of displaced customers whose claims we are trying to settle. People will be compensated in due course."
Egg has launched a new rewards credit card which gives consumers a typical 10 per cent cash-back on purchases at over 1,500 retailers.
Cardholders can browse through offers from participating retailers on Egg's online superstore. The cash-back amount varies depending on the retailer and is credited back to the cardholder each month.
The card offers new customers 0 per cent interest on new purchases until September 2010. The card charges a 17.9 per cent variable rate.
Fixed rate bonds
Santander and Alliance & Leicester have launched a new range of fixed-rate bonds paying up to 3.5 per cent. Savers can choose from terms of one year, 18 months of two years and the minimum deposit is 1.
Elsewhere, Santander has launched a 'Hat-trick' mortgage deal at 3 per cent for three years with a 333 fee. The tracker product is available to all Homebuyer and Remortgage customers and requires a 25 per cent deposit.