The info in my manual is a little different...but here's some tips of things you could or should have inspected ...
Oil and filter
Coolant, brake fluids.
Check drive belts for damage, adjust belt tension if needed
Inspect steering gear box, linkage and suspension
Ball Joints and dust covers, drive shaft and steering rack boots, chassis nuts & bolts for looseness or damage.
Inspect brake linings, drums, pads, discs, lines and hoses
You could take your Celica to any auto shop to have those things checked, whatever you prefer. It seems $800 for your last visit seems pretty extreme. But I think just a basic check to make sure things are in order will give you peace of mind. Then you just have to make sure to schedule regular oil/fluid changes ,etc. You won't have to worry about changing trans fluid on your auto for another 100k miles. Also your spark plugs are fine for about 77K miles.