I've had pretty good luck with Mile High with ~$1 books. They are usually very competitively priced on cheaper books and have relatively good service. Their "NM" books are hit and miss, though, and you should stay away if you are a high grade collector. I have had some great luck with "Fine" books that I would grade "NM" with off white pages.

Pricing on key books, bronze age and earlier, and many recent issues is often much higher than anywhere else in the market. Other sites like mycomicshop.com or certain eBay auctions will often give you a much better price.

As others mentioned, I've had a couple problems when I've ordered one printing of a book and received another. I've only ordered cheap books so it wasn't a huge deal but I woul've been pretty mad if it was a more expensive book. Volume is MH's game so you really can't expect them to be perfect.

Yeah, the website is a joke but MH is a good place to order from. Be sure to subscribe to Chuck's (MH's head honcho) newsletters where he included "code words" that will often give you a 50% discount on advertised prices. I usually save up a big want list and then order on a rare 50% off key word.

Hope this helps!
-Bob