Family Radio Service (FRS) radios are inexpensive and available from many local and on-line retailers. You probably want to have a few around in various places so one is handy wherever you are when something happens.
FRS radios usually come with rechargeable battery packs which work fine most of the time. All FRS radios can use regular AA or AAA batteries instead of their battery packs. We recommend looking for FRS radios that use AA batteries if you haven't already bought them as they last longer if you are using the radio. Keep at least two sets of batteries with your radio in case the power goes out. That should keep you going for a while. More batteries are better than less.
You need to set your FRS radio to channel 9 (unless your neighborhood has agreed on another channel). We recommend that you use tone 0 (no tone). The instructions on how to set that up came with the radio. You might want to write down the instructions in your own words on a card you keep with the radio.
Now comes the important part! Take the batteries OUT of the radio(s). Put the battery cover back on the now empty radio and put it, the batteries, and any instructions or accessories you might have, into a zip-lock plastic bag. This will protect the radio from corroding batteries and should keep the batteries from discharging for a long time.
You should take the radio out, put the batteries in, and test it every once in a while. If your neighborhood has a monthly net get-together and you have multiple radios, use a different one each time to make sure they're all working.