The horizontal top tube, canti brakes and threaded non suspension corrected fork are also out of place on a 1998 bike. The wheels also look like 26" with slicks not 700c so it could originally have been sold as an mtb.
I'd put its value at $125 max. Less if the drivetrain shows wear and will need replacement soon. The Suntour stuff is very difficult to find today, but often there are suitable replacements floating around.