If you are looking for a budget AGA here is some general advice for you:
I have owned an AGA since 1996 and cleaned a few hundred over the last seven years. I currently have three AGAs:
AGA number one is a gas powered flue in a house I renovated which I now let. This AGA I bought from new in 2000. It seems to work very well though as I haven't lived in the house for seven years I have lost track of house expensive it is to run but I've got an idea that the price of gas has doubled in the past seven years so a reasonable guess would be about £80 a month and a service once a year is about £120.
AGA number two is the AGA in my current home we have a 30 Amp AGA which I bought renovated from Mr Cooker for £5500 (total price including fitting) in Dec 2007, and it still looks like new. It seems to work fine though I have had to replace one element this year and two last year. Each element replacement costs £150. Cost to run is – I can be accurate with this as it heats on an off peak meter – is £10 a week.
AGA number three I bought an AGA on ebay about a month ago for £123 for my training kitchen in our office. It is a PRE 1974 which means it has a step at the back of the enamel top. Here is a photo of it on this blog AGA Cleaners AGA . Really it was a great buy as it looks like new and is a reconditioned one. It had a broken burner which I think contributed to the price. I have looked at kits to convert it to electricity. GB cookers have quoted me £1800 to fit the kit they use, that is re build my AGA with the kit. It is made by Hytech Enamellers who with GB Cooker also make renovated electric AGAs with the same kit (about £5500). Hytech AGA conversion kit. Mr Cooker also quoted me the same price for a kit made by Midland Cookers. GB cookers have told me that their AGA would cost about £16 a week to run. Mr Cooker told me that they achieve this by putting lots of insulation in the AGA to keep the heat in. Hence on the Hytech page they mention it is safer for children. So the Hytech Eco Cuisine seems to cheap to run but there is a trade off with the amount of heat. Though at the moment my kitchen is at 40C so their AGA might not be a bad idea at all. Our AGA keeps all our house, except for our front room, warm though.
When the AGA engineer replaced my element on my 30 Amp last month he mentioned the unreliability of 13 Amp AGA and mentioned that even though they have warranties the owners still have to pay for the call out and first half an hour. So this is £100 a time to get it fixed. The fault is normally in the PCB board and this is just replaced. Obviously when it is out of warranty you'd have to pay for a new PCB board too. So beware of not very old 13 amp AGAs on ebay as they be an unreliable one. The engineer also mentioned that one of the customers he has seen with a 13 amp had a proper meter fitted to her 13 amp AGA to get an accurate record of cost of running. The meter said £6 a day! Though saying this about 13 Amp AGAs my wife's good friend has had one from new (three years old now) and it hasn't gone wrong at all and she swears it only costs £20 a week to run – on AIMS.
So from this you may want to think about getting an older AGA on ebay and getting it converted with a kit. Though you'd need to be aware that dismantling and assembly costs can be expensive. So ideally an AGA on ebay that has been dismantled. If it needs enamelling a company like Hytech can do it for you. Though it is going to cost about £1500 for the whole AGA to be renamelled. And then in addtion to this you'd need to pay for an electric conversion kit. Not sure how reliable these are but if you get a warranty perhaps they are okay. Alternatively you can get one that is renovated already from some one like Midland Cookers or GB Cookers or Twyford Cookers but the cost is about £5000.