Every card is inspected individually, and you receive a detailed quote
I've often theorized about a Planeswalker that had static text that said something like "You can activate this Planeswalker's abilities on the opponent's turn" or "You can cast your spells as if they had flash," so seeing these implemented is very exciting.) Jace's static ability, however, has a much different role to play here than card advantage: he's basically a Laboratory Maniac
Other land cards shown in the most recent stream actually appear to be variations on existing cards
Enchantment Loading Zone If one or more counters would be put on a creature, Spacecraft, or Planet you control, twice that many of each of those kinds of counters are put on it instead
Well, just like anything else, the price is decided by supply and demand, and as you might imagine, the supply is low and the demand is high