great question!
;
at this point, there's a few different markets driving demand for minis;
Imperial Assault (the miniatures are of a comparable scale if not directly in quality),
folks that want to complete their collection etc...
non-English backgrounds, who like Star Wars, but couldn't access the minis back in the day (they were rare in South Africa, South America and Russia)
being in Great Depression 2 and a lot of folks being "FIFO" and moving a lot,
that's all contributed to devaluing miniatures. It's a dying art.
people also don't have as much cashola anymore.
Minis are somewhat undervalued compared to when the sets were new,
and compared to that 'scarcity window' in the future where even though millions of units were made,
minis just can't be found.
I've seen a few collections
some with all sets sans MotF and GaW etc,
sell for $2800 - 3500 USD.
all together, in a lot at one time.
all mint A1 grade, minis still in bag, the cards stored in an ultrapro deck holder.
doing the math, on the units per lot, it winds up being ~1.13USD per mini regardless of rarity.
Whether thats a breakeven or a win-win depends on what the collector bought into it for hehehe
More frequent collections I've seen sold are incomplete and B grade at best,
with some damage to the maps and cards, fading etc...
and those usually go for ~$1300USD max for 1100 odd pieces.
you see these sold on Ebay and Amazon or Craigslist etc.
You may be able to obtain more value via breaking the lot up into different subcollections,
or via a collection house/auction house if you have all associated memorabilia etc
theres also being able to sell as small lots via gumtree etc...
hopefully, that gives you a sense of what it can be worth.