You can get cheap 24V PSU's on eBay...Input AC110-220V Output DC 24V Regulated Switching Power Supply For LED Light | eBay I got the 24V 250W one (although I got mine from Hong Kong) for driving 4.5A. LED strips only take a couple of hundred mAh depending on how long your strip was so you won't need anything too large! Also most LED's are 12V so you will need to factor that into the equation. Why don't you get a 240V to 12V LED PSU transformer like this one 18w LED Driver Power Supply Transformer 240V - DC 12V | eBay?