Nexus are rolling out more beta testing, starting on 21st July.
Members of the public have been selected to try out the PAYG Pop Card - which works on Metro and a limited number of GNE and ANE services (as well as the Stanley Travel services above), within Tyne & Wear, Co Durham and Northumberland.

As with Oyster, fares are reduced when using Pop on the Metro, with daily caps put into place. A maximum of £4.40 being charged.
Bus operators aren't offering discounts as it stands, but the card can be used to buy the usual ticket.

The Pop Shop will be launched on 21st July too, with PAYG options being available.