Newbie looking for some help on first purchase

[Uglyducky]

Hi all,
Wondering if anyone can put me in the right direction for a rough price point and package (what is a complete package) for a datejust or similarly priced men's watch. The prices I see are all over the place ranging from $2200 to $6k for this watch. I don't know what makes one more valuable than the other. Have been looking for a month now as a gift for my lady I'm open to buying pre-owned but really want a LNIB example if I do that. I am in Los Angeles if anyone has any suggestions locally. I was really hoping to get it done around $3k and have had a few offers for watches at that price with box and paperwork (although I don't know what all should be in the paperwork). What are the most important things to look for? Thanks for any help?