Does anybody know anything about these guys? They supposedly "cut out the middle man" and have the best prices: https://diamondsdirect.com/heritage-of-60years

Real Diamonds cost real money.
Assuming a person is looking at VVS1 or Flawless. D or colorless
To get the fire out of any size it come down to the fine points.
Angles,percentages, table size,girdle width and consistency etc. That's why there is such a difference in price for what seems at first to be the same stone as another.
Whatever you buy have it rechecked . You would be surprised how many certified are not as stated.

Thanks everyone.
There's no Costco in town, we have a Sam's Club but I'm not a member.
The only pawn shop in town is a regional chain - PawnAmerica, and they charge about the same for used stuff as a jewelry store would charge new. I'm not sure what I'll do. She works this weekend so maybe I'll do some looking around.

Go to one of the on line sites. Seriously, they're less risky than shopping at a mall. If they sell something that's not as advertised they would lose their site. They're less protected than a Mall jeweler who can claim he told you the diamond was cheap when he saw of it to you because you have a perfect paper trail of what they sold you.

Call a couple of the online sites, tell them what you want, and see who gives you the best price. You'll get something that's not even available at any price at your local jewelry store or even a Costco or Sam's.

Doesn't Sam's Club have One Day temp. free pass?
.
Can't afford the $45 Sam's Club membership?

What I meant was...would you not be willing to spend $45 to find out if you might save several thousand? ;)

FWIW

Old estate jewelry. You will not see many people wearing the same style or item you just bought while out in public. The items have a genuine life to them. Find a jeweler and ask them if they have any. If not or if the prices seem high move on or negotiate. Just because an item is asking does not mean anything. Wife has a ring given her by a previous beau, she tried to return it several times and he kept refusing it. Retail cost was around $3K maybe more. Return charges to sell back? $599.00 which is the wholesale cost.

I also ask, why diamonds? Rubys and pearls and citrine and so many other choices. Very nice items will definitely stand out.

Take her to Antwerp....vacation, diamonds, what can go wrong

I did quite a bit of looking today - all the online sites listed here seem to run around $1000 to $1100 for about 3/4 tcw studs. Sam's club, about the same, here's a link.
https://www.samsclub.com/sams/0-70-ct-t-w-round-diamond-stud-earrings-in-14k-white-gold-h-i-si2/prod7320408.ip?xid=plp1656-jewe:product:1:4
Edit - Pelican seems to be munging the url, trying to add an emoji to the url. Sam's club item 756423.
I couldn't find a similar offering at Costco's website, and like I said, there's no store close to me.
I did check eBay, I'm wondering what's the catch with nyexquisitejewelry? 20,000 positive feedbacks, about 1/2 the price of the ones above. Like these, for instance -
.75ct 3/4ct ROUND-CUT G/VS2 GENUINE DIAMONDS IN 14K SOLID GOLD STUDS EARRINGS
or
.75ct 3/4ct ROUND-CUT G/SI2 GENUINE DIAMONDS IN 14K SOLID GOLD STUDS EARRINGS | eBay

Or these? $53?
.95 CT Round Cut Studs Earrings Basket set Screw back Solid 14K White Gold 5mm | eBay

I've skimmed this thread...

I want to see pics of the two 25 year olds.

Bad news on that front. I mentioned the plan to the fiance, and she agreed to it, under the condition that she pick the girls. She picked her daughter's two best friends, and while they are wonderful young women, I can only put up with them for a couple hours at a time. Alcohol helps, at least if I have some but not if they have any.
I guess while that was an idea that sounded good in concept, when you look at reality I've got it pretty good. I guess that's why I'm looking at diamond earrings. She'd like to wear them for the wedding.

Just to close out this thread - I ordered a set of earrings from nyexquisitejewelry on eBay. Listed as .80 carats, F color, VS2 clarity. What they didn't mention was the cut, which was not ideal. The table is not symmetrical, and some of the star facets are different size. One has a small blemish going from the table to one of the facets. But they are sparkly enough, and the fiance loves them. You can't see any of this without a jeweler's loupe. The settings are large and strong, so I don't see them falling apart any time soon. I'm happy with the purchase, and they were 1/2 what the Costco diamonds were.

She sounds like you found a winner with that reply! Congrats.