If you buy an item online and pay with Paypal they have a promotion where if you change your mind they will pay the return shipping costs. It runs to the 31st August and can be used 4 times up to a value of £15 each time. You need to opt in and it appears to be valid for all Paypal users.
Could prove useful for some..
Sometimes, when you receive the item you bought online, it isn’t quite as you expected. If that happens, simply return it and don’t worry anymore about the return shipping costs, it’s on us *. The service is free and valid also on international shopping
Update - Email received this morning (4th July 2016) to say the offer has been extended until the 31st December 2016 -
“Return Shipping on Us.*
Activate this service for free and we'll cover up to £15 of return shipping costs for up to 4 eligible PayPal purchases worldwide until 31 December 2016.”