depends what you call low priced. but anything below £100, well there are some logiecth z550 i think they are called. apparently quite good, then there also ipod docks you could use (if you have an ipod) that have got aux in, that way you get two in one.
there are also Bose companion 2 which sounded reasonable, but also were very clean and tidy (ie lots less wires than other systems). but for portability i would go for an ipod dock, most likely the Logitech dock or a cube one, i cant rmember what its called but looked and sounded good