The eBay one, the other uses proper high wattage resistors for the mains side connections.
As to electric prices I pay about 14c US per kWh, but it is slated to go up by at least 20% per annum for the next 5 years ( long story, contracts to massive smelters that pay 6c per kWh and no escalation for inflation ( you can bet there was an envelope passed there) along with having to pay "preferred" suppliers) at least.