Why is this Djinn the cheapest card of the Epic rarity bunch? Is she weak? Does she not pack a strong enough punch or utility? 3 magic damage in silver and easy triage proves this card is badass in as low as silver-league. Against a single sneak attacker, she'll just heal your backline after every punch. Despite bringing good stats and skills, this card's price is the lowest.
This isn't because Renova lacks power. It's just that the other Epic rares are really, really powerful, much better than what she has to offer. Lava Launcher not only stuns, but he's also a very good last-position defender with great Repair synergy, which is something the Fire Splinter has come to abuse a lot. Uraeus is generally very powerful, under any splinter. They're both better and more useful than Renova.
Although Djinn Chwalla is more powerful than Renova, it fails prominently in its splinter: most non-tournament players don't use the Dragon Splinter often. The chance of it being enabled in a match is slightly lower and summoners are either way more expensive or just plainly suck compared to other options. Why even pick him up if you're not going to use it as much as any of the other rares? That's why Chwalla's price matches Renova.
If you're not sure of how much better a printed card is better than other printed cards, you can safely guess by looking at its price. If it's good, it's more expensive. Venari Wavesmith is a testament to that idea. Keep up the place with the Splinterlands' card market!