Is it a good idea to look at online marketplaces like eBay to find a (used) notebook ? Is it a good idea to buy a used one or should one go for a new one ? Buying used ones has some advantages over new models: The price will be considerably lower, even if the used one has been purchased just a few months ago. Prices for last generations notebooks drop fast, even more if they have been used already.
You normally get no warranty whatsoever unless you purchase it from an merchant who sells his goods at eBay. This may be a disadvantage to some but it could also be seen as an advantage. Not many people would open up the notebook and take a look inside to maybe replace parts if there is still warranty on the notebook. For example if you purchase a used one that has a hard drive with 20 gigabytes of space you could try and replace it with a bigger one.
The guys from notebookreview.com put an article online that gives you valuable hints for purchasing a Notebook on eBay (and other online marketplaces).
They put up a checklist of questions that you should ask the seller before you bid or make the purchase. Most will be hopefully explained in the items description, everything that is not should be asked.
Get deals on select Lenovo Notebooks, Desktops and accessories at the Lenovo Rebate Center

Essential Freeware Utilities for Notebooks
Replace the Playstation 3 Hd with a bigger one
One guy describes a sweet alternative to laptops that costs a hundred bucks or so.
http://os.newsforge.com/os/06/02/22/2221258.shtml
If you already have a laptop or just access to one, I guess it will boot that too.
http://wiki.grml.org/doku.php?id=laptops