HP LJIIp and LJIIIp printers - get them working or dump them?

I have 1 LaserJet IIp and 3 LaserJet IIIp printers. None of them are really usable because the toner cartridges are either out of toner or the images have streaks and blotches. I think all of them are functional electrically and the paper feeding is still OK. It has been 3 years since I last tried one. I could always use an extra printer, so I have to decide if I should get them working or just dump them and get something new when I really need it. Is there a source for GOOD toner cartridges? Google finds a bunch of cartridges, but how many are junk refills? I am willing to pay for good cartridges, but I can't tell good from bad. Are feeding parts available if they start to pull multiple sheets, etc? Are there reputable sources? I know these have a good reputation generally, and I used one for a long time in the '90s. -chuck