If you can't take Pianoman's advice because price is a barrier, then don't buy a pair of boots because they worked for someone else. Most every brand makes their boot volume to that brand's specifications. Find a brand that makes its volume fit your foot--that is probably the most important fitting issue that doesn't get addressed by retailers. A really great boot store can help you with that, but is hard to find. I wear La Sportivas because they fit my foot, but that doesn't mean they will work for you.
Spend your money on good insoles, they may be more important than the boot! Superfeet, Sole, or Lathrop custom insoles are worth the coin--about $50/pair. Lathrop's website has some good basic information on boots, fitting, and foot care in the backcountry.
The money you spend on your feet (boots, insoles, socks) is the most important money you will spend.