I've found several old MacBook Pro's (before about 2013) at yard sales with asking prices of about $10 to $25. All have had dead batteries and some have had their insides so clogged with dust and gunk they shut themselves down. Common answer to the sellers about why they were selling them was that the "don't run latest Apple software and too expensive to repair". What I do is bring them home, pull them apart sna clean out everything using a combination of a air compressor and non-residue alcohol cleaner. Then reseat all connections, RAM and other connectors. Remove and discard battery and replace with one for about $30. A couple of them I have had to replace the HD, which were bad. Used a cheap 1TB SSD drive which attached no problem. Then, installed Mint Linux and everything worked fine. Very fast too. WiFi, works as does the video camera and microphone. BlueTooth is problematic, but used a small form dongle so as to use a BT mouse. Bottom line, for about $75 or $80, I had a well-working laptop. I've given those to a local charity which then gifts them to disadvantaged school kids (read, very low income White Kids).