What do you want to do, and what other devices are you bringing. A Delta global day pass is $28 if you buy it before flying. There are other passes that you can buy in the air, one of which is the global day pass (for more money) but some of which are mobile passes and phone passes and are cheaper. I forgot what any of these cost, except for an instant message pass (which doesn't include Skype) which I bought for $4.00.

t-mobile has 1 hour of gogo Internet for free, for a phone, and then free access to several IM services for the whole flight.

With a laptop, just hook up using any browser you want, but to find out what's the best value for your needs, do some research. I tried to find out how much these things cost if you buy them in the air, but a quick check didn't yield the information.

If you want a global pass that works with a laptop, either buy it on the ground, or if you fly enough to justify it, you can get a global Delta plan for $69.95 per month, or a global multi-airline plan for $79.95 per month.

Again, for a single flight, a global pass bought on the ground is $28 - unless you can find it cheaper, in which case I hope you let us know about it.