I'd recommend you use these standard 40-watt tungsten bulbs. They are under $1 each and you could use 10-30 of them to make a reasonable-size ring that will run on a standard household 15-ampere 120-volt circuit. This should be plenty of light for digital cameras.

You can use the US-made 120-volt bulbs on 240-volt EU power by wiring the bulbs in series-parallel, two bulbs to a set. The total wattage is the same.