You can plant them this spring, but don't plan on harvesting anything this year - you should pick off all of the blossoms. Let the roots get good and established, and you'll have a nice harvest next season. Remember, good things are worth waiting for! :watering
Be careful of the sellers. I've gotten some of those 30/$5 deals before, and all the plants were teeny-tiny runners that were half dead (not dormant, dead and rotten, or dessicated) and didn't grow well at all.
Best I've ever gotten from dormant plants has been Nourse Farms, they charge $11-12/25 plants. The plants were decent sized, and the deer thought they were delicious.
If you order everbearing ones for delivery now, this very minute, and plant them in NC, you might get a handful of berries at the end of summer.
I got a great deal on some grapes last year at the farmers market and the dog thought the spot I dug them in and watered the soil well was perfect to dig back up and lay in the cool hole......