But I realised that my best investment was my RealClassic shed mug. It cost around £5 and I use it for my essential morning cappuccino when I'm working in London 3 days a week. Pret a Manger give you a 50p discount if you take your own reuseable cup, so that saves me £1.50 a week. Say I'm working for 46 weeks of the year, that means I get £69 each year.
My most inflation-proof buy yet.