talking from hindsight…
If your wrist is not too big, you can start off with the following pre-owned
Rolex 6694.. 34mm.. you can get a pre-owned for between 5-6K but its manual wind, no quick set date but it is a classic and will never go out of style.
IWC Mk XV or XVI abt 5-7K depending on condition.
Omega for RM 5-7K will probably be ETA based 2500 movement models, not the in-house 8500 or 9300
I didn't recommend a pre-owned Grand Seiko as most ppl can't accept a 'Seiko' costing 4-5 figures… but preowned is pretty hard to find anyways
That's another great watch where I own 6 pcs, bought brand new
The above is a good start, better than most of us when we started…
there are too many 'nice looking' watches but watches with solid proven in-house movements and that will never be out of style, are few and far in between….
rm5k?
pre-owned omega?
brand new longines legend diver...after discounts of course 
pre-owned omega sounds nice!
where can i get good quality pre-owned watches that would be in my budget?