The AC adapters for my 2 dell laptops wore out very quickly.

One supplies power but won't charge the battery (it's about 3 years old, the other is a bit newer).

Both have worn through to the shielding around the notebook connector and look like they'll be unusable soon.

Checking user reviews of the replacement adapter on Dell's own website, it appears they usually fail this fast. Apparently Dell does this deliberately to make money (their adapters sell for about 10-15 times what they cost to make). Same with replacement batteries.

I can see there are plenty of much cheaper ($50 less) compatible AC adapters on eBay. Does anyone have experience with these? Naturally I'm nervous a crappy knock-off could fry my notebook, but has this ever actually happened to anyone recently? Has anyone had a good experience? Can anyone recommend a good online seller (who doesn't charge nonsensical shipping costs to Australia, preferably?)