Where can I use an unlocked iPhone 5?

I bought from apple online? I'm do confused how it works. I don't want a contract plan

If you purchased your iPhone 5 unlocked and without a contract, you may use it on any GSM (SIM card) prepaid plan, domestically or internationally.

For the US, you have several choices for GSM carriers (search the internet for additional details):

1. GoPhone
2. Red Pocket
3. Straight Talk
4. T-Mobile
5.Net 10

Basically, you will obtain a SIM card from the provider of your choice. If you decide to pay month to month, without a contract, you just have to ensure that you have credited your account to be able to use your iPhone for that month.

Many of these plans come with unlimited everything for about $45 per month. There are many options, just be sure to openly communicate with them and ask as many questions as you feel necessary. Take care.