I would take a look at Base Ball Card Exchange's buy price list.. that should give you an idea of what a dealer would pay for them.
http://www.bbcexchange.com/viewuserd...aspx?pn=buying
Early 80s stuff is actually starting to heat up a bit.. At one time 81 Topps Wax could be had for pretty cheap and it's getting harder to find and the price is going up.. Hell 86 Topps is even going for a bit more as the PSA Registry junkies seek out the elusive Gem Mint 10's from the set. Sandberg is tough to score in good shape.
As the 70s stuff has dried up and caused higher prices a lot of people are moving on to 80's product that is still somewhat affordable.
I say take a look at Steve's buy prices on the Baseball Card Exchange website & also at sold results on ebay and make an offer you feel comfortable with.
$300 for all that would be a steal..
I am confused though you list 1983 Donruss Cello.. I am pretty sure they only did wax and rack packs that year.