The second is paying a total boat load of life to do so
The trick is to exile something like a Mana Geyser as your second card to have access to tons of mana every time you play a Dragon's Approach
Hello and happiest of days to each of you
That said, collectors are a driving force in Magic's secondary market, and as soon as you put a number on a card (beyond its power and toughness, anyway), you're going to get people willing to spend more than $250 on it
Though it isnt much use at all in the modern game, given its stats, its clearly a highly unusual Charizard, which is likely why its so valuable now
As a result, Dialga ex pairs just as well with Pokmon like Regigigas (whose damage-scaling Raging Hammer attack requires four energy), Wigglytuff ex (whose Sleep Song attack puts active Pokmon to sleep), and Pidgeot ex (whose Scattering Cyclone attack deals more damage based on how full your opponents bench is)