Was thinking about this topic when i was in Wickes about an hour ago.
Bought a poofy decorative trellis/fence panel thing, the slats of the trellis are glued together, and one of the joints had come unstuck, nothing a drop of wood glue and 2 mins of my time wouldn't fix.
I took it to the till, he rung it in at £22.50, i said could I get a bit of discount cos its damaged etc, he needed authorisation from his manager to do the discount. So the manager comes over, says we'll do it for £20. I said 'but a tube of decent wood glue will cost more than that discount.'
So he said £15, I said ok then. He started knocking it through the till, and I said, 'You said a tenner didn't you?'
He said 'go on then, but I'll be putting the price up on the next thing you buy from us'
Cheers passionford, you saved me £12.50, don't tell the manager of wickes I've got a tube of wood glue in the shed though