Wifi will either be free or you will have to pay locally, ie to the hotel you're staying in (usually by the day). If you use the 3G connection on the iPad (if it is available) then you will attract what might be eyewatering charges when you get home and receive your next phone bill.
Mobile phone companies charge for 3G, wifi can be provided free or with a charge by almost anyone with a wifi connection, pretty much like if you give out your home password to someone (although I'm sure there'd be terms in domestic wifi contracts to stop you charging)
If your iPad is 3G it might be worth ringing your provider to ask if they do a bundle of data for abroad at a reasonable rate), you'll still need to find a wifi connection for the camera though.
Does that make sense?