IBM NOTEBOOK HARD DRIVE 30GB 4200RPM MODEL # IC25N030ATDA04-0, PART # 07N6714 - OEM, DRIVE ONLY TravelStar 30GN 2.5 inch/9.5mm ATA-5 2mb Cache Buffer 12.0ms Average Seek Time - 3 Year Manufacturer Warranty - 30.0 GB

$142 (newegg.com) - Cheapest trusted source I know of.