PSP Versions
There are four versions of the PSP: the original, PSP-2000, PSP-3000 and PSP go. Refurbished original PSPs, which are the heaviest of all the models, are common because of how long they have been available. A refurbished PSP-3000 or PSP go will be harder to find and will cost more than the original and PSP-2000 models.
Price
As of June 2010, a refurbished original PSP costs around $100. That is $70 less than a new PSP-3000. The extra cost of a new system may be worthwhile not only because you are getting the latest technology, but also for the peace of mind you get in knowing that it has never been opened and used--and possibly abused--before.
Contents
The original box, manuals and memory card will come with a new PSP system. Most refurbished PSP systems are sold with just the system and power adapter. So to save game progress on a refurbished system, you will have to purchase a memory card.
Warranty
A new system has a one-year warranty. A refurbished system has a 30-day warranty. An extra one-year warranty is optional and will add around $30 dollars to the overall cost. An unopened system comes with a one-year warranty out of the box.
Dead Pixels
A common problem with PSPs is dead pixels in the screen: pixels that have blackened and will stay like that forever. Any dead pixels you find after the refurbished system's 30-day warranty will not be covered.