I have a different opinion of Sportsman's guide.
Quite a few years back, I ordered 2K of .223.
I was sent a confirming email of the order.
I don't know what to say I've no association with SG other than as a generally satisfied customer, but a quite few years ago ammo prices didn't fluctuate wildly, perhaps it was a web site error. I've heard of companies honoring ridiculously low prices on website errors just for the good PR, too bad SG didn't do so for you.
Another possible reason for the glitch was a while back the parent company was sold, may have taken the new owners a while to realize they would be destroying the value of what they bought for minimal gain with such actions.
But at the end of the day, unless you've found an ammo source cheaper than or equal to SG you are cutting off your nose to spite your face by "never buying from them again".
Only issue I've ever had with them is if I order "too much" ammo for their $19.95 shipping charge they sometimes try to hit me up for extra shipping at a much higher rate, in which case I cancel the order. I then reorder in multiple orders as long as case of ammo + $19.95 - $10 coupon is less than the competition -- often is, so I've got a lot of ammo from them over the last 10+ years.
I've also had good luck with returning stuff that turned out to be crap, if you contact them they'll Email a FedEx or UPS prepaid return shipping label. They seem to be playing FedEx against UPS lately as some recent stuff has come via FedEX some other via UPS, used to always be UPS which gives much better service at my address than does FedEx.
The key to getting ammo on-line is the total $ammo + S&H + tax(if any). In stock is good but unless I'm totally out, these days I'm happy for a back order that "locks in" a price, as ammo availability improves if prices sink enough I can cancel any higher priced backorders.
My most amusing return was a 10-pk of "used" Yugo AK mags for $60. One had a bullet hole in the side! The other few I looked at were so deformed the bottom plate popped off when I compressed the spring. Returned them for a refund, no problem. Such happens with "true surplus".