Hi Omari,
this is what I'd suggest.
1, take your time. don't rush into just buying "any old" Omega.
2, work out what you want. If possible try one on ( at a watch fair ? ) pick it up, handle it try it on. I have found ( through experience ) that some watches look great in a pic, but when you get hold of them, they are "dissapointing" ( too small, too flat etc etc )
3, Once you've decided what you want. Look for one. I heartily recommend eBay. I have bought MOST of my watches there. The prices are usually way lower than from a dealer. But as Georges regualarly points out, you don't usually get a guarantee etc etc. But you do get an idea for the market price.
4, should you decide against eBay ( some people do ! ) there are LOADS of internet dealers. Chuck has a MASSIVE list. Here is Chucks list please note he has a link at the top of the page to a 2nd dealer list.... you will spend hours looking through these !
5, If you do your homework correctly & choose wisely, Should you buy a watch that you decide not to keep, you should be able to sell it for what you paid ( or if you're lucky make a profit ... which quickly disappears when you buy your next watch :-) )
There are many many vintage Omega models out there. There are many many examples of each model. Feel free to come back here, ask questions about any watch you might be interested in. Hopefully everybody learns from a post.
I hope this helps
Steve