Prices have skyrocketed on all traditional HD's since the floods - OEM's snapped up every single drive they could when the floods occurred and the retailers had to jack prices up. Being an opportunist scumbag that I am, I bought 8 WD 1 TB internal drives for $55 Canadian a pop one day on sale from TigerDirect while supply was still decent.
$99 was about the best buy I could find for something that would fit the bill for you - I had an older one of these that worked great, required no external power, etc. I paid like $60 for it a few years ago, needless to say it's more expensive now. Amazon may have some better deals, or eBay. One I had came with a nice little neoprene sleeve case, worked well.
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136750
