The godaddy appraisal tool shows many, or maybe most, domains being worth $1,000+ but they aren't worth that in reality. You can buy domains that they appraise at $2,000+ for $10.

If you saw a .com domain sell for $5,000 then it doesn't follow that the ,net may be worth $500. Sometimes they might be worth that but more often they're not really worth anything.

If you PM me a list I'll let you know what I think. I've sold a few domains in the past and have started selling again.

Where to sell? The best way to sell is to contact businesses that could be interested in them. If you put up for auction the buyers, if any, are more likely to be other domainers, so you'll get wholesale not retail price for them. If you just list for sale you could be waiting years to sell them. It's not at all easy to sell a bunch of domains.