What Is The Value of These Coins?

My buddies girlfriend works at a bank and someone came in and cashed some first day of issue SBA envelopes. I don't have scans because they're not in hand but she did show them to me when I was over at their place for a couple of cold ones the other day.
Here is an eBay link ( not mine or hers - so don't think I'm spamming
) of what exactly she has. It's three envelopes like this auction pictured but both times I've tried researching it I could only find one auction at a time. Yesterday one ended with no bids and today that one pops up which appears to be from a different seller. One of the three she has caught my eye in which I didn't see any hits but I'm sure would have to be examined under a loupe. What, in your opinion, is the value of these envelopes? Thanks.
Here is an eBay link ( not mine or hers - so don't think I'm spamming

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Comments
Ask a coin person, and he'll tell you they're worth whatever UNC SBAs are.
That might not be far from the truth, in any event. I don't expect the first day covers will command that much of a premium over the value of the coins, but I don't know. Probably just a very tiny bit.
She ain't gonna be able to retire off the proceeds, but still, if she got 'em for face value, she's doin' just fine.
Here's a recent completed eBay auction for 4 of these in the envelopes.
SBA Auction
Looks like they went for 3X face (including shipping). 2X face w/o shipping.
lordmarcovan - Yeah, I'd assume myself that she is doing decent getting them at face even though there isn't much of a premium. But hey, I sure thought they were interesting looking. Never saw them before.
RedHerring - Thanks for the auction link. I don't have an eBay account so it was something I could only search for with current auction listings.
All in all, I'm guessing these would have more value in a high graded attributed slab then in the envelopes.
The stamp is a 15 cent Scott # 1597 Ft. McHenry Flag stamp issued 6/30/78 Stamp alone on a FDC, value $1.00
The three caches have a July 2, 1979 Denver, Philadelphia, and San Francisco cancellation, . I’m sure the Susan B’s have the mint marks from those issuing cites.
I would put a value of no more that $7.00 per envelope, they are rather neat and well made, cross-over for philatelist and numismatists.
"Keep your malarkey filter in good operating order" -Walter Breen
Hoard the keys.