1. Before you start listening to all the people who tell you to rely on webwallets or other third party providers, consider using an SPV or lightweight Bitcoin wallet.
Electrum seems to be most commonly recommended, but there are other options as well depending on your preferred platform. Simple Payment Verification means you don't have to worry about bandwidth at all, but as a tradeoff you may sacrifice a small amount of privacy. But you'll be in complete control of your own keys, which is the most important part.
If you don't want SPV and prefer to opt for a full node, Bitcoin's current total blocksize is just over 130 gigabytes, so yes, you're going to exceed your 30GB cap by some margin if you want to get synchronised and up to date in one single hit. Monthly usage will be even higher than that:
https://bitcoin.org/en/full-node#minimum-requirementsIt’s common for full nodes on high-speed connections to use 200 gigabytes upload or more a month. Download usage is around 20 gigabytes a month
2. I'm not a big fan of Apple, personally, but people generally speak favourably of
Breadwallet. Security largely depends on how you use your device and what precautions you take (I run with the NoScript browser extension, so javascript is disabled by default unless I specifically allow it to run on the particular website I'm on). If you're not doing anything risky with your computer/tablet/phone/ etc (and have innocent browsing habits
), any OS should be relatively safe. As a general rule, most people are more likely to be scammed than hacked. But webwallets and other websites that hold bitcoin get hacked quite often, so keep them on your own device(s). Try to only do business with those you know and trust.
3. Some people swear by paper wallets, but I'd only go with those if you have a safe to keep them in. Otherwise, securely passworded (or better yet, passphrases with lots of words and non-words) backups in cold storage (not connected to the internet). Not just one or two. Lots of backups. And then store those backups somewhere relatively secure as well.
