If we assume you play Nassif's recent UW Affinity deck below, replacing two Thoughtcast with two Heists, and you are able to cast Heist on Turn 5 for two mana, then you have 22 remaining hits in your deck out of 48 cards
The idea here is to play a bunch of fast mana and low-cost spells to quickly empty your hand before your opponents, then Timetwister, refilling your hand while disrupting your opponents
While they are typically valued around 100 to 500 JPY (~US$0.67 to ~US$3.37), powerful cards can be sold for over 1,000 JPY (~US$67.74)
You could build your deck in such a way that you always flip into powerful spells, but that strategy cares more about cascade than exalted
These range between $5.99 (for the deck boxes) and $19.99 each
In battle, it stops the opponent from activating cards or effects