Printing one off and going to the shop all see the same effort to me, both are nice gestures. Making one if the way to go though for real effort! (y)
Effort would entail actually going to the card shop to buy a card or making your own. Not print off a pre-made template.
Most dads would appreciate any effort made by their kids :)
Nothing says "I love my Dad" like downloading an image from the internet and handing the stripy inkjet A4 print to him. An even quicker way is to just use Google Image Search and send it to his phone. XD
Gonna print one for a mate of mine as he didn't get a birthday card this year, not cos i'm nice i'm just being a **** and rubbing it in LOL.