PostSnap, an app like Moonpig has large, glossy personalised Father's Day cards on offer at £2 each including first class postage (usual price £3.79). The discounted price ends on Thursday. For a crafty additional saving use promo code NEW10 at checkout for a 10% saving which means the cards are just £1.80.
Here's the link to the app - appsto.re/i67f9Lx