Hi,
I run a retail shop in the UK and I am considering accepting Bitcoin.
I don't really understand how to do it.
I know I can create a QR code but do I need a QR code for each item I sell?
So, the customer comes in and wants 3 things, how do I do it?
Sorry if this makes little sense.
I think you're talking about how to separate the payments, right?
You can think of each public address (also represented as a QR code) as an individual account. If you control the private key to that address you fully control the account. It's possible to use Bitcoin with only one or two accounts, but for reasons like privacy it's advised to use more, and every account (public/private key pair) can be created quickly and freely.
Just to get started and get familiar you may want to use only one account/QR code for customers to pay. Then simply watch the transactions at blockchain.info/address, for example:
https://blockchain.info/address/1FMaLBrEM4nkCn15CoAeykb912jr7AfuwVBy watching that screen you can see each individual transaction which comes in. So you hold the QR code for the customer to scan and send their coins while watching that address on blockchain.info which will have it show up in a few seconds. It will be unconfirmed of course for on average 10 minutes.
So the customer wants 3 things, you give them a grand total as usual then find how much that is in bitcoins (divide total by bitcoin price) and have them send payment to QR code address.