Well, upgrading will not be available in the pre-alpha, but the concept is that your road is forked. If for instance, you go for a green foil upgrade, you might get increased health or taunt, a blue one would be an ability like flying which ignores taunt, and gold would give out key abilities.

It would totally depend on the type of deck you want to craft. Having a deck full of flying (ignoring taunt) would obviously be strong against a taunt deck etc.

In terms of cost, too early to decide if it will snowball into "thousands of Euro" but we don't intend to go that route, and will do whatever is needed to make the game accessible.