If you’re passionate about owning a full box, I would take the plunge on the 1991-92 set sooner rather than later. $75-$100 may sound like a lot, but for a 48-pack box it’s still only $2 a pack or less, won’t break the bank.
For the 1985’s, the economic pragmatist in me would take a look at the 1986 album sticker set, which reprints many from the 1985 as well as some of the 1973-76 originals. If you don’t mind the smaller format but would like to get them cheaper than a 1985 box, look into it. I’m sure Greg’s site has a complete checklist you can reference to see what titles are in the set. One caveat though - there is a collation issue such that a single full box may not guarantee a full set. I think some boxes only contained 44 of the 77, and others the other 33 of 77. Again, Greg’s site probably explains it more accurately than I am here.