Yes, so in other words:
cost = 8
text = "Whenever your
creature dies, add a random
card to your deck and regain one third of the card cost."
I'd use it. It will make
pheonix decks pretty ugly. In order to be rid of your pheonix they will have to kill it twice, giving you back 2/3 of the cost and 2 random
cards. This will make players think twice before killing off fire creatures, which are otherwise often quite fragile. With a soul catcher or two in place, you might even be able to thread this into an otherwise mono
deck.
An even more potent alternative would be:
"Whenever your
cards is destroyed, add a random
card to your deck and regain one third of the card cost."
Then this works for destroyed
permanents as well (creatures - ashes, permanents - dust... or maybe vice versa)