Watch for 500$ or less

Tissot Seastar is a good option my friend

About twenty F91W's bra

I'll recommend a Marathon Navigator, it's a great watch that is a bit different, and fun. The tritium tubes keep it readable in the dark, and the quartz movement means it's always set to the right time. 

If you're into the "history" and "heritage" stuff, Marathon has been making actual military watches since 1941, and still makes them. The Navigator was designed for the USAF for long range missions, and was designed by a member of the family that founded, and still owns the business. 

Any tank watch is the ideal female gift. 

If you're on a mission for a Grand Seiko, you could take the money that would be spent on a new watch and apply it towards the GS. But where’s the fun in that!

As @KristianG mentioned, the Marathon Navigator is a great choice. You’re Terrific has a good video on it:

https://youtu.be/hfmlwnOieLA
 

Recently squired the Seiko SNE573 38.5mm solar diver that is incredible  for the price (~ $350 on eBay) if that’s your jam; highly recommend it. There are also plenty of micro brands with a lot of bang for buck. Nodus and Lorier are a few brands to look at / keep an eye on. Happy hunting!

Seiko 5-Sports SRPD87 if yer into classic divers.

Seiko SUS Reissue Nano Universe SCXP155 derived from the impossibly cool IWC Mark XI.

So many options.  So many options types.  Might depend on watch style you're looking for....

Or if  you shop well you can probably buy 3 Seiko 5's for about $500.  In which case you can get a Seiko "5KX", Seiko 5 Field and a Seiko "DressKX".  Which gives you something to wear for just about anything.  

If you want a single GADA type watch..maybe a Tissot Gentleman.  

Swiss choices:

Glycine Combat Sub below 400 

Tissot Chrono for under 400

Hamilton 429

Hamilton Khaki Field under 450

 Japanese or Japanese Movement

Samurai under 400 

Turtle Under 400 

Seiko 5 under 300

Under 300

Under 250

Microbrands: 

Dan Henry 1964 270.00

Phoibos Narwhal 480

Islander Racing :

Hemel 499

German

Laco 410

As you can see 500 is nothing to sneeze at you can get some great pieces. If you go mint used your options just doubled. 

Alright I want to add some to the mix that haven’t been mentioned:

Starting with the RLG Odyssea (around 450$) my favourite diver. Really clean look. Good quality and high beat movement.

Another really cool vintage diver: spinnaker fleuss (300$)

NH35 I think so no problems on that front. Also many Color options. I think it’s inspired by the fifty fathoms from the 50s if you’re into that. 
 

Now a field watch: the SWC Bunker around 450$
nicely sized titanium field watch with incredible Lume and AR counting to the moon and back. 

Aaaand the Dress watch: Seiko SRPE43J1 500$

Show me a more stunning dial under 500$ and I’ll give my collection to my Mailman. :)  btw he has this one  too. 

i own or have owned all of the watches above and love or have loved all of them I think you can’t go wrong with any of them. 

I would check out Seiko, Hamilton and Laco, among others. 

Also, the new Timex Q GMT looks awesome and it's just around 200:

I thought the watch you labeled as Hamilton 429 looks beautiful but I can't seems to identify it. Can you confirm the name of that watch? I meant the one that looks like a Jazz master with an inner red ring. 

Wow does this look like a $500 watch? No sir, it does not.

Hey, you can't buy your wife a piece of furniture for her birthday!  That should come out of the domestic account. 😂