If you really want to have playlists that hop between internal and external memory, one method is to use the alternative firmware called Rockbox, which will do that.
Another is to use playlists in the .pla format rather than the usual .m3u format.
As for price, Amazon fluctuates constantly. I got a refurb 4G there for $20. You can also look on eBay for refurbs–just check the seller’s reputation, obviously.
