Martin,
OK, time to be serious (for once). You can pick up either driving lights or foglights at Halfords for £20 or less per pair. Add on a fuse holder and a relay plus some wires, crimp connectors, shrink sleeve and a scotchlock for tapping the main beam wire and you have a setup for less than £30. But then you need to mount them on something. MiGSel's light bar is nice but chop up an old kids McLaren buggy and you get a nice straight piece of aluminium spar that will serve you well. You can then get a bit more sophisticated by adding an autoswitch (or normal switch) and extra relay to run them independent of main beam. The choice of driving lights or fog is entirely your preference. Driving lights are like main beam and illuminate everything - more suited for main beam augmentation. Fogs have a flatter wider beam that "fills in" the road surface in front of you and is therefore better for dipped beam augmentation.
As for my bike, my cheap Ring Ice Blue driving lights were crap and leaked like a sieve. My replacement cheap Ring fog lights are superb.
Mike