I clean for a living. If I offered my services for a charity raffle, I do it not only to help the charity, but because it's great advertising for my business where I get to showcase my skills and get my name out there.
I only use professional products and materials that I've carefully selected over the years because of their quality and superior results.
If the charity said "give us a list of what you use and we'll buy them for you", and I ended up with an inferior 99p all purpose spray from Poundstretcher and one cloth & one duster, I couldn't do my job to anywhere near the high standard I usually do. It would in all honesty, be a really shit job!
So, that's my reputation down the pan! A reputationIve spent years building up. I've tried to showcase my skills and expertise, but haven't been able to because of inferior, and not enough, products and materials I would normally.l use. Why would anyone want to recommend me to friends, or write glowing reviews online, or book me again?
So, on that basis, I'd cancel. Because they are putting my business reputation at risk.
It's all good helping out a charity on one occasion, but not at the expense of your business reputation suffering in the longterm. That's unreasonable of the charity to expect.
And quite frankly, there's nothing worse than someone who thinks they know your job better than you do, telling you its possible do it just as well 'for cheaper' because its 'only cleaning / only cooking / only whatever'