What are these G1 boxed Transformers worth?

Looking to sell these, but not sure what they are worth. Already had one offer of $500 for all 4. Is that the best I can hope for?

Edit: Don't know what happened with the pics...look right on my iPad...shoulda put this in off topic maybe? Sorry about that. How can I move it?

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Bump it to $600 and it's a better deal for both parties.

Figure they're worth an average of $200 each via retail/eBay.

B3G1Free for a private local buyer willing to pay out if no fees/shipping are involved is nice. (even $550 would be cool)

If it's an anonymous online buyer, then they're slightly lowballing you at $500.

Condition of the figures is a pretty big deal for most collectors- if the stickers and stuff are in good shape, I think Kerig's number is good if you are doing it locally and in cash. It's low but selling valuable collectibles is risky online. 

On a side note, super jealous of your TFs. I always wanted some of the G1 TFs but unfortunately, they were before my time and way to expensive by the time I had money to buy any.