Tesco appear to be selling 2 packs of the 50W Halogen Spotlights in their £1.00 'Bargain' boxes.
I dont know if the deal is being run nationwide but this appears to be a pretty good price for these (50p each). They appear to be selling for around £0.85 each on Ebay for a boxset of 10...even more for individuals.
Current location is Dunfermline, but I hope it may be elsewhere too. If, like me, you always seem to need these, I hope this is of interest.