My original equipment seatpost is described as the following: Suspension, 45mm travel, 350mm x 27.2mm, alloy clamp with QR seatpin and is pictured below. I need to get rid of this movable menace and am looking for a good, relatively lightweight replacement.

Will any 350mm x 27.2mm seatpost work as a replacement? I'm looking for a good carbon seatpost under $100 or the best/lightest aluminum seatpost.