As mentioned above you can get a lot of bang for your buck by buying used or nearly new on the classified section of this website, ebay, Craigslist, etc. I would highly recommend 1 oversized bag with frame capable of 100+ lb loads for yourself. Your kids likely can't carry as much so other packs may not matter as much. I would concentrate on at least 1 super high quality pack/frame for yourself so you can get the brunt of the load. If it were me I would keep my eyes open for a 6,000+ cu in Kifaru or Stone Glacier bag and frame. A larger back can be cinched down tight to the frame when not fully loaded and is plenty big for hefty/bulky loads. It's tough to beat Kifaru or SG. If you buy a used Kifaru or SG you can likely sell it at the end of the season for the same price you bought it for....they keep their value super well!