I would expect come late February to early March that used prices will inch up a little as people start scrambling for markers for the season. With that said I'd say NT10s will be $550-600 on average.
I've always found that the best time to buy used markers for strictly price is between World Cup to February, especially WC to Christmas. That's when people start selling off from the past season and needing money for Christmas. Then come May/June prices start to go down again...