Go online to your Dashboard/front page & buy from there - you can also set up for it to reoccur (the same as a Goodybag) when credit gets down to £3.00
AIRTIME is a PAY- AS-YOU-GO allowance which is used for Multimedia Message Services (MMS), used abroad, for outside the EU area & for 070, 084, 087, 09 and 118 numbers & lasts until your credit runs out. And for the first 3 months after top-up you have free giffgaff to giffgaff calls.
AIRTIME Charges: Calls @ 25p a minute, Texts 10p, Data 5p per MB, Voicemail 8p a call.
Picture messages (MMS) to giffgaff and other mobiles (max 300KB) 30p per MMS
(Goodybags do NOT include MMS)
Click on this link to see all Calls & Tariffs to UK mobiles: https://www.giffgaff.com/pricing