Get this with free delivery. Will last AGES! This is 1 litre. I got 500 ml and still have 2/3 left. Having cleaned my windows every week.
http://www.amazon.co.uk/Greased-Lightning-Crystal-Exterior-Protector/dp/B007S8EPB2/ref=sr_1_15?ie=UTF8&qid=1454361084&sr=8-15&keywords=showroom+shine
https://www.tetrosyl.com/images/stories/virtuemart/product/images/TET/TETTWW/TETTWW100/TETTWW100.jpg
Get the microfibre cloths on Amazon. Can get a whole pile of them for £5. Go for the white ones. They won't colour run in your washing machine!
http://www.amazon.co.uk/Greased-Lightning-Crystal-Exterior-Protector/dp/B007S8EPB2/ref=sr_1_15?ie=UTF8&qid=1454361084&sr=8-15&keywords=showroom+shine
https://www.tetrosyl.com/images/stories/virtuemart/product/images/TET/TETTWW/TETTWW100/TETTWW100.jpg
Get the microfibre cloths on Amazon. Can get a whole pile of them for £5. Go for the white ones. They won't colour run in your washing machine!