Replying to Used ski help

thinking i want to grab another pair of skis, prob jeffs/mangos, or some sort of ski like that. is my best bet just scouring marketplace, or should I just save and buy new. any tips for buying used skis. I.E best places to look, what some decent prices are, and how to tell if they are in decent enough condition. also if anybody has a stiffer rockered park ski that they would like to sell me, let me know. i am interested. appreciate it.