All cleaned up, re-greased and tuned up, I get $125-$150 for an 820 with original components. Nice step up from the 800, cro-moly frame and a step above entry level components, sometimes Araya rims.
Messed with it for few this morning before work and it seems like the shifters are gummed up, tthey move smooth but won't hold a gear. Hope to get to work on it tonight after work.
If you carefully take the covers off the shifters and squirt some wd-40 in there, it will free up the pawls and they will stay in gear again. Common problem when those shifters are old and haven't been used in a while.