The common little things I've encountered with my '99 4runner came after 100,000 miles. It had 84k when I bought it and it was all working great. The common maintenance things were the leaking axles (inner) seals and starter contacts. The seals aren't all that hard to replace and or the most part don't take any special tools. I can do one complete in about 45 minutes. Problem is that if you let them go for awhile they will contaminate the rear pads and require a brake job. The starter contacts aren't too bad either as long as you can get the starter out. The contacts are copper pads that will wear out. Cheap fix considering an starter from the factory is $$. I have the 5 speed so I had to replace the shifter seat bushing but it's a couple little parts and 2 tools. Check out 4runners.org for a great site that has everything you need for maintenace (and more). Bob, the creator of that site, hangs out at Ultimateyota.com
In all I've been very happy with my '99. It was in great shape when I bought it and I take care of it so it's still looking and working great.
