While the more valuable versions of Charizard are the original versions of the fan-favorite Pokmon, there are plenty of other newer cards featuring the character
Logging and looking these up manually would take a while, so I decided to see if I could automate some of the process
Price estimations from various sites have this deck coming in between $65 and $85, with only a couple of cards coming in above $5 in the least expensive iterations (which run the Universes Within versions of the Stranger Things cards)
Similarly, if you sacrifice a creature to activate a mana ability while activating Heirloom Epic's ability, that creature won't be on the battlefield when you pay the ability's activation cost, so you won't be able to tap that creature rather than pay one of the mana in the activation cost
When cast for five or less mana, this will draw you two cards at best, putting it on par with cards like Divination