Miriam, I'd be tempted to split them up with you; but after carefully going over the photos, I just don't see a lot of value. The machines are in pretty poor condition, it seems they have spent years in an unprotected environment, and many of the machines exhibit the beginning signs of rust on the outside. Which means rust on the inside, and that's a problem for smooth thread travel over the bobbin.
What's interesting is that the woman's late husband appears to have had a method to his madness--many of the Singers are model 99s and La Vencedoras. However, most of them are models from the 1920s (note the large spoked handwheels), meaning each and every one would need to be rewired, as wiring insulation typically doesn't last for 90 years.
I also see at least one natural-born model 15 treadle, which is a good machine, but the finish appears to be in terrible condition, like it was stored outside. If you look closely you'll also spot things like a 66 missing the slide plate.
Bottom line, $499 seems like an attractive price for that many machines, but rust, missing parts and damaged finishes can often be more trouble than they're worth. The bentwood cases caught my eye for their potential value, but again, they do not appear to be in great condition.
If any of you do end up bidding on the machines, please keep the rest of us posted on if you found any gems in the collection!