You'll need some kind of data plan (medianet, etc.) Then if you can install Opera Mini (a 3rd party browser) you can surf the internet with that. You won't be able to download applications to the device with it but it will browse the net ok.

The Gmail app will check your gmail account (if you have one.)

Having a mac only makes it harder to load the applications to the device. I recommend finding a pc, loading Desktop Manager to it and using it to install Opera and Gmail.