I don't understand paper wallets.
Hi FinShaggy, what do you mean? That you don't see the usefulness of papaer wallet and cold storage?
No, I don't understand how you get a coin from a wallet to a serial number or barcode or whatever. I don't really understand how they put information in a barcode either...
This is exactly what I did not understand either! Well it turns out all you need to do is sent an BTC amount to the bitcoin address that comes with the private key. As somebody mentioned earlier, the "value" of your paper wallet will be sum of all transactions at this address.
EDIT: For others also looking for clarifications on how to use paper wallet. This is what I have understood so far (could be a little wrong):
1. Paper wallet services allow you to create a "bitcoin address + private key"
2. You can print this information on a piece of paper; art is optional
3. To load this wallet, send BTC to the listed address. You can send multiple times and the value will be equal to sum of all transactions.
4. When you want to spend the money, use the private key or scan the code with a suitable app.
PS: There are a billion concerns about security, apparently no computer or system on the planet is hack-proof. See somebody is standing behind you and looking at your puter:)