Having stumbled through to my mid-twenties on a archaeic mix of personal music technologies such as "tapes", "minidiscs" and "listening to music through speakers in the privacy of my own home", about 5 years ago I got my first MP3 player. The player in question is a Cowon Iaudio X5 (which is very good by the way, especially with rockbox) but over time the battery has been dying and a year or so ago I managed to drop the mean time between intermittent failures on the disk to about 2 days by unceremoniously propelling it across the office in a cable-tripping-over incident. Instead of buying an iPod I decided to have a go at fixing it:
New battery (ebay) : £10. 32Gb CF card ( MyMemory) : £45 (it was on sale currently seems to be about £60). CF- 1.8" Toshiba adaptor ( LinITX) : £10 .
Opened case, removed drive, de-soldered old battery, re-soldered new battery (make mental note, buy a new nib for soldering iron and some flux, curse EU for banning lead solder), reassemble.