If you know someone in emergency services blue light card - get them to download you the coupon just keep a print if it at home or copy on ur phone.
What other ways? Before I had 10% of everything and that drove me there. Now being just cycling I tend to shop at Decathalon and other sport shops.
I suppose it depends what you want it for. I got 4 x cyclocross folding tyres rrp 29.99 each for £14 recently (for all 4). To me I save well over the membership a year and make money flipping stuff that's reduced then had discount in top but there are lots of other ways to get 10% off at halfords.
Only valid for cycling... a bit meh to be honest.
Thanks for posting (y)