Literally hundreds of on-line shops are registered with EasyFundraising. All the big ones are there: Tesco, John Lewis, B&Q, M&S, etc., etc. You should be able to get almost anything that you might wish from food to fridges!
When you want to buy something from one of them, do not go directly to their website, go to www.easyfundraising.org.uk. If you have not done so before, register with the site and register that your preferred charity is the Clan Macpherson Museum Trust.
You then select the link to the On-line shop that you want to use. That click tells the On-line shop that a small percentage (typically 1.5%) of your bill is to be donated by the shop to the Clan Macpherson Museum Trust.
Amazon donates 0.5% of the net purchase price (excluding VAT, returns and shipping fees) of eligible purchases to the charitable organisation of your choice.
Select the Clan Macpherson Museum Trust as the charity of your choice and the museum gets the benefit of your shopping at no cost to you. Register at smile.amazon.co.uk.