Like just make them cost 3k to upgrade, and just lower the card cost
(Cept with sundial being free/purify/Snova etc
My idea for the free costing cards, just adjust the effect of the card slightly. Such as:
Sundial, cost 1 less light to draw, or make you draw 2 cards with 3 light cost, or something of that sort (Or change the element to draw with)
Purify just make it do the same effect but heal like 1-2 health.
Snova make it cost 1 less entropy, or keep the same cost and make it give 3 of all elements, or 2 of all +1 random element.
Animate weapon could be free, or just add a +0/+1 to the weapon.
(And for the cards that shouldn't be decreased in quantom cost (IMO) is firelance etc (Just increase the damage by 1)
Thats all i can think of atm, anyone else have any suggestions?