I now have the EasyYo maker and it works a treat, you just use cold water to mix the sachet of stuff and bouiling water to fill the outside container and leave it overnight. One sachet makes a litre, enough to last me about a week with my muesli.
I mostly use the Greek yoghurt with honey, which is absoloutely delicious, but I vary it from time to time with other flavours. They cost about £12.50 for five or six sachets, depending on the variety, so there is no need to eat tghe same flavour all the time, you could change it weekly if you wanted to (more often if there are two of you eating it)
I buy it online from Lakeland every ten weeks or so. Delivery is free above a certain level (can't remember whether it is £30 or £35) and two boxes come to £25 or £26. The extra is easily made up with cling film, foil, cleaning products and so on.