Comment Actiontec Mi424WR (Score 1) 376
http://www.actiontec.com/products/product.php?pid=189
This may be what you're looking for. Offers 10/100 WAN ethernet interface, NAT, the whole she-bang.
You can find them used on eBay for under $40 shipped. I personally used a pair to utilize a coax line in my office for hard-wiring my desktop as my wireless was being spotty. Through put is better than 802.11g and ping times are in the 3ms range.