Just went to get a bulb for my car (£10 for standard bulbs) but buy one get one free on Super Brilliance and Extreme Brilliance bulbs (up to 90% brighter).
I thought for the sake of £10 I might as well try them and absolutely amazed at the results! £40 worth of bulbs for the price of £19.99 and the quality is amazing.
Some of the bulbs were cheaper than £19.99 but it depends on the vehicle make and model - visit their website and enter your registration to check price.
I'm not sure how long the offer is on for but they had ample stock in the Coventry branch.