It's fully airgapped. No internet. No wifi or bluetooth.
An airgapped hardware wallet communicates with apps using QR codes.
The benefit of using an airgapped device is that it has no connection to the internet, which means hackers can't reach your keys, which means hackers can't steal your coins. And the benefit of using an airgapped hardware wallet with a large screen is that it shows you what you're signing.
ok wow that's really cool! thanks for the nice explanation.
Aside from Ledger reputation and history, cheapest Ledger HW on it's official website is $79[1]. I also think the page doesn't include tax and shipping fee, although it's at normal price. On a side note, you could build DIY Jade (based on Blockstream Jade[2]) which cost less[3] if you don't mind less feature.
i know it's not recommended but i was looking at ledgers on ebay. but they claimed they were "new". but i think i like the idea of using an opensource software and hardware like the yahboom better!