Free football kit vouchers â cost you Â£127. Npowerâs Football 45 gives you up to Â£90 of vouchers to spend in any Football League club shop-but the gas and electricity tariff at the heart of this deal is Npowerâs standard tariff which is Â£127 more than the cheapest tariff* currently on the market.90. This is Â£27 a year more than a standard tariff due to the Energy Extra 50 service charge. Repairs are charged in addition to your monthly fee. Only guarantees same day or next day latest engineer visit for central heating (when experiencing either no heating or hot water) and fixed priced repairs.