Buyer has paid twice - how do I refund?

[justneedsomesleep]

Newbie buyer has paid me for something twice (checked paypal account). I'm assuming they will realise at some point, so how do I refund them their money?

At least i think they have! Shows up twice in paypal - not a glitch anyone else is experiencing is it? It's for £1.99 and they have never bought or sold before.
Just want to be prepared.
Thanks,
Pollyprincess78

just click on item details in paypal will give you option to refund

Many thanks.
Unless of course the buyer intentionally wants to give me more money!