Not tried it myself but worth a go to avoid delivery fees.
http://www.dailystar.co.uk/tech-news/440752/Amazon-20-minimum-spend-for-FREE-delivery-can-be-avoided-with-this-simple-trick
http://www.dailystar.co.uk/tech-news/440752/Amazon-20-minimum-spend-for-FREE-delivery-can-be-avoided-with-this-simple-trick