Here are 2 more sites:
This one is an online seller. http://www.pocketwatchsite.com/walthamserials.html
I would buy my watch on eBay from a seller with a near 100% rating and at least several hundred reviews. Confirm the watch works. There are many good American pocket watches from Waltham, Illinois Watch, Elgin and Hamilton, among others.
You may also find a nice watch from Patek Philippe or Omega amongst the Swiss makers, but American made watches were really classics. The solid gold watches obviously will be more expensive, as will one with a chain.
Just do an eBay search for pocket watches and you'll be able to easily browse hundreds quickly to see what you like. I buy almost all my vintage wristwatches on eBay. You'll find a fine pocket watch on eBay in your price range.
Well, I am not the best person to ask because I don't collect pocket watches. I think that site is good for information. You have to understand that my interest is vintage watches. With pocket watches you are looking at an antique, not some crappy Chinese pocket watch imitation or ghastly, with a quartz movement.
The American railroaders all kept the rails running on time with their railroad pocket watches. Some of these are over 100 years old. Many have beautiful engraving. There's nothing like popping open a pocket watch with a decorative spring cover. American watchmaking in the 19th and early 20th century rivaled that of Switzerland. They are really an authentic piece of history that you can own. All the great American makers are gone now. So I am not a fan of a new pocket watch. It means nothing. Older watches, as long as they are running, are a better choice IMHO. The ones that need repair run the risk of a broken balance staff that can be costly or impossible to fix. Other repairs are more easily done by a jeweler. Avoid listing that say "for parts"
I'd buy an American made antique or vintage watch from the brands I listed, on eBay. If it comes broken, eBay will back you up and get you a refund. The Swiss watches are going to be much more costly. I think you can get a nice vintage pocket watch on eBay. Here's an example...a work of art
You must get one that is running and serviced. Avoid solid gold as the gold value drives up the price. I think you will have to spend $200-$400 for a nice watch. Post a link on eBay that catches your eye and I will tell you what I think. Search eBay for each brand I mentioned earlier.
And under $100, you can get something very decent that runs
Here's another vintage piece of Americana form 1941
Didn't Capt Spaulding have a pocket watch? Or maybe Rufus T Firefly.
Say, did Rufus get pensioned and retired to Red Button's place at Century Village?