The most important item to check when buy a used laptop

is the battery.

You should test the battery by fully charging the battery

and checking the laptop runs for a reasonable amount of time,

about 1.5 hours or more.

A replacement battery for a laptop is around

$100 to $150

Laptop needs the battery even if you do not

plan to run the laptop without being plugged in.

The plug in power supply for a laptop is designed

to charge the laptop battery and NOT support

the heavy loads of starting up the laptop

or under heavy use loads such gaming, playing music, and or loading updates.

Also charging a bad battery will burn out

the laptop plug in supply over time and

is a FIRE HAZARD from possibly the bad battery exploding

Also you should test the hard drive

see our tips page

How To Test a Computer Hard Drive

Other repair costs to consider are items such as broken screens

which cost $200+ to repair.

Note: with New laptops costing only on the average $400 to $600

not $1000+ of a few years ago, most used laptops

are NOT worth purchasing.