£30 is waaay too steep for me, for that it should come with a USB battery pack heck why not for a little extra money just throw in a whole battery compartment and make it a mini prodigy! I am done with passthroughs that don't have an in-line battery, they are far too much trouble to power, no ordinary USB port is good enough which kinda defeats the purpose of it being USB!!
--EDIT-- Ehhem excuse my rant, you see I have not had much luck with passthroughs hehe!