There are 2 offers I have found for FMP £1 for a month (2015).
To be used by 1st May...
http://www.findmypast.co.uk/origins
After that runs out there is... (to be used before 1st July)
http://www.findmypast.co.uk/waterloo-200
Make sure you go to your settings and deselect the Automatic renew.
The 20 free credits offer also seems to still be active...
http://blog.findmypast.com/2013/new-rec ... irst-time/
There is also a recommend a friend offer (std price but with M&S voucher)
http://www.findmypast.co.uk/recommend-a-friend-fmp
Personally, I prefer FMP to Ancestry as they have a great many Staffs Parish Registers (go to search, A-Z and type is Staffordshire)
Happy Searching!