AGK is a very logical language and IMO very easy to pick up, especially if you get Daniels book, that'll take you right through all the things you need to know.
Really, I think with a card game like you describe, the biggest task will be the artwork - once you have some workable art, it's very quick and easy to get it into AppGameKit and behaving how you want. For example, say you had a single image of card faces, 8x8 cards on the image at say, 256x256 each (best to stick to power 2 sizes). The AppGameKit code to load that, and create a sprite for each card would look a bit like this:
LoadImage(1,"cards.png")
CreateSprite(1,1)
SetSpriteAnimation(1,256,256,64)
For s=2 to 64
CloneSprite(s,1)
SetSpriteFrame(s,s)
SetSpritePosition(s,random(0,500),random(0,500))
Next s
Do
Sync()
Loop
That little bit of code loads the image, makes a sprite from it, then clones that sprite 63 times and sets the frame so each one has a different face - then positions them randomly and loops through a standard main loop.
Seriously, I'm a long toothed hobbyist/indie developer and I've used pretty much everything out there - AGKv2 isn't the cheapest option, but it's an investment that will go somewhere if you can put in some time, there will be a crazily successful indie game made in AppGameKit before very long, I'm sure of it.
I am the one who knocks...