A laptop under 100 is very low.
You would be hardpressed to find good quality and brand new laptop at this price range if any.
However, you will probably able to find a good quality used laptop below the price of 100.
Here are some of the availble ones that you can take a look at:
Dell Latitude 2110, Intel Atom N470, 10.1″ Refurbished Laptop With 2GB Memory, 160GB Hard Drive, Windows 7
Dell Inspiron E1505 15-Inch Laptop (1.67 GHz T2300 Intel Core Duo Processor, 2GB RAM, 60GB Hard Drive, 8X DVD+/-RW Drive, 802.11b/g WiFi, Windows XP Media Center)