With an Easiyo yoghurt maker you can buy the sachets to make yoghurt by just adding water or you can make yoghurt by mixing a tiny bit of bought yoghurt to milk. We tried the sachet route and it made nice thick greek yoghurt but at £3 a time it's more than we wanted to pay.
Next we tried making yoghurt by mixing yoghurt and milk but the yoghurt it made was far too runny.
Third time lucky we tried adding powdered milk to the recipe to thicken up the yoghurt and it worked!
Replace the lid and shake until it's all really mixed together.
Fill the Easiyo container with boiling water up to the fill line and put the smaller container inside.
Leave for 8-12 hours and then refrigerate the smaller container of yoghurt for an hour or two to have cold yohurt.
Then you can enjoy your yoghurt anyway you like. I've got a tablespoon of lime curd to mix into it in the picture and it was delicious.
Making the yoghurt this way costs about £1.35 for a litre of yoghurt which is pretty good I think.