Cant help much on the skis, but as far as the bindings i paid right around 200 for new freerides after shopping around A LOT. It looks like my boots are similar in terms of entry level at boots with three buckles rather than four. I paid about 300 for my boots again after shopping around quite a bit. Used skins I personally wouldnt pay more than about 80 for unless they are practically brand new. New skins range from 130 to 170. If i were in your shoes i would try and get the bindings for 100 or less and the boots for 150 or less. Add that to the skis and you would have a very reasonable entry at set up imo. A note on the skis, i bought used skis from a ski area that were lightly used, no core shots etc. The skis retail for 900 w/o bindings and i got them for about 300. Maybe that gives you a reference to go off of.
I went the Craigslist route and wound up paying $375 for those same bindings, a pair of Black Diamond Mira skis, and like-new skins...everything in top flight condition, just a few years old and used about 3-5 times. I've found similar deals on craigslist, so if you are patient there are great deals to be found!