How to pay for something with BitCoin: first set up an account on one of about fifteen different sites, possibly with dodgy-as-fuck security. Then you have to wire some money to some BitCoin exchange which is 100% guaranteed not a scam because someone on bitcointalk said so. After the Russian mob takes a cut, you then can transfer some of that money into a wallet. Then you can spend your Bitcoin… somewhere. That is, if the site that was cobbled together by a moron in Rails or PHP in a week doesn’t get completely owned in the meantime. Be sure to take the time to learn the difference between a cold wallet and a hot wallet, and what buy/ask spreads are, and take the time to jockey all the money between the relevant wallet. And keep an eye on the market just in case the value of your BitCoins plummets because one of the not-at-all-hacked-together exchange sites goes tits up because of shit programming.
How to pay for something with evil, government-backed fiat money: go to vendor site. Click ‘Pay with PayPal’. Type PayPal password in. Press pay. Done.
Let me call my gender-non-specific non-technical family member. I’m sure they’ll be ready to switch to using crypto-currencies right away. I’m sure they won’t think the whole thing is a massive fucking scam.