Now is an ideal time to plant berries as long as your ground isn't frozen (which I'm sure it's not) and isn't too wet. Do be careful about sourcing your plants from craigslist. You may not get virus indexed plants and you may not even get the best varieties for your area. I prefer dealing with a reputable nursery that sells quality plants and will stand behind them if a problem occurs. You can get blueberries, blackberries, and strawberries sooooo cheap from any of quite a few really good mail-order nurseries, that I can't think of a good reason for dealing with someone on craigslist and taking the gamble.

Which kind of berries are they selling? Are you sure it is tranplants not someone just buying cheap bareroots and reselling them? (Are you sure you can grow them in your area?)