Philip Elmer-DeWitt in Fortune:

If you buy the digital editions of Popular Science or TIME Magazine on the iPad, they cost $4.99 each — same as on the newsstand. However, one-year subscriptions to Popular Science (the paper magazine) are currently selling for $12 — or $1 an issue. And TIME subscriptions can be had for $20 — around 35¢ an issue.

Why the disparity? And, why so much money for a digital version vs. a paper version?

Because that’s what the market will bear — at least for now