I've got some great Lodge prices on ebay. Currently ewins_corp has the Lodge Logic 5 qt Dutch oven for $24.99. One thing to keep in mind is that cast iron is heavy, so your shipping charges will add up.

If you live close to or travel by Cracker Barrel restaurants, they sell Lodge cast iron. Very inexpensive as compared to other prices I have seen.

Cast iron is often cheaper at local hardware or cooking stores. As PhatCat points out, it's heavy, so a local place that uses truck shipping (buying many items simultaenously) often incurrs less shipping charges than using UPS.

Ace and True Value, which use company trucks, don't care about weight, because they will also be carrying cases of AC filters and light bulbs at the same time, so the weight really make no difference.

I've seen what appear to be excellent prices on Amazon.com. Only $8.99 for a Lodge Logic 10-1/4-Inch Pre-Seasoned Skillet. $26.99 for a Lodge Logic 5-Quart Pre-Seasoned Dutch Oven. With free shipping for purchases of over $25 (only items directly from Amazon.com, not 3rd parties through Amazon.com) it should be even cheaper than eBay. Plus they have a coupon running through November 27, 2005 for $25 off of $125 or more of Kitchen & Housewares or Bed & Bath products. Promotion code WTRQUCKDSCNT. I'm thinking of loading up.

Here is a link that might be useful: $25 off purchase details

WalMart carries a fairly good selection of Lodge Cast Iron cookware. Sams Club has had sets for sale around the holidays.