Apple releases the second iteration of its iPhone today. The product ostensibly carries a lower price than the previous version. But how much does it really cost? Matt and Marnie both pointed me to the latest comic from The Joy of Tech, which explores this very subject.

Would you forego an iPhone for a million dollars?

Be sure to read the math behind the comic. Some of the assumptions are a little loose — 10% market return, no inflation — but the point is still valid: the extraordinary power of compound interest is a wonderful thing, and always worth considering before you make a big purchase.

(By the way, I’m not saying you shouldn’t buy an iPhone — and neither is The Joy of Tech. Just make an informed decision, and don’t get caught up in tech lust and gadget envy. Personally, I own a first generation iPhone and have no plans to upgrade.)