Scott O80 24c I Believe

Hello I am not very familiar with this type of stamp and interesting in your insights.
I researched it in Scott specialized and believe it to be the O80
I am not clear on the various cancels and variants that might affect its value and rarity, but this seems like a standard issue O80 to me.

I do see a wide range on eBay (of course) so unclear what I may be missing or not understanding.

Much thanks in advance

As you've seen on eBay, O80 is found with a wide variety of cancels. It is the third commonest 24c departmental stamp at 100,000 delivered to the department. O91 (War) and O22 (Interior) were issued in grater numbers, 200,925 and 134,125 respectively. This information is in John N. Luff's The Postage Stamps of the United States.
Pen cancels like yours may have been used from a small post office, but most high value official stamps with pen cancels were favor canceled, also called a "Presentation copy".

Yes, it's O80.

First off, go by "sold" listings on eBay if you are looking for a valuation guide. Sellers can say anything and offer at any price that they want, and they are not necessarily more knowledgable than you. And genuine sale prices on eBay are usually somewhere between wholesale and retail prices, probably closer to wholesale for a US #O80.

The pen cancel would reduce the value of this to about a third of its "normal" value. EDIT: A presentation cancel wouldn't reduce the value. But this has the look of being genuinely used. Heavy smudge cancels, though normal, also reduce the value though somewhat less. The stamp is off center (pretty normal also) and has small corner creases and a dirt smudge. It may also be reperforated. Those reduce the value a lot. Now, that's not to say the stamp is unworthy of collecting, but that it's just very low value compared to (say) the Scott value which is for a better-centered and sound stamp.

With any of the Officials, check the paper as they can be several types. These two, O78 and O79 are on Intermediate paper. If you are unfamiliar with the reference, it is as it sounds, between hard and soft paper.
The cancels on these two are much more common on Treausury stamps