Who Do You Think You Are Magazine (behind the TV series) is running a huge sale on back issues of the magazine through the iPad/iPhone/iPod touch Newsstand app for $0.99:
Who Do You Think You Are? – Immediate Media Company Limited (iTunes)
Single issues normally sell for £4.99 / €5.49 / $6.99, with normal subscriptions costing £3.99 / €4.99 / $5.99 per month, or with a 1 year subscription, £44.99 / €49.99 / $64.99.
I believe the back issues stretch all the way back to April of 2012, at least going by what I see in Newsstand.
There is a also a free 1 month subscription trial, which includes the latest issue. The app itself is free. This is the same “Who Do You Think You Are” that is behind the popular genealogy series in the US, UK, Canada, and elsewhere.