Patience is your friend, Benjamin is also your friend when it comes time to buy.
Don't try to negotiate over email, every seller has a list of people who want to pay less than their asking price who have never even bothered to look at the machine.
Go and look at anything local to you that's remotely suitable, even if the price is silly, because it will give you more knowledge.
I can think of one person on here who bought an older machine and really regrets it, but his need is for a business he's running. Most of us are hobbyists so having to do some refurb or repairs is just a good chance to learn more about the hobby. If all you want to do is just turn out parts then it makes sense to focus on only known good new machines but if you see this as a journey in learning then even overspending on a used machine can reap benefits far beyond actually having a particular tool. Time you spend setting up, fixing, and improving your tools gives you a much deeper understanding and builds confidence in ways that just buying something never will. Think about it this way, you can go buy the best guitar out there but if you don't practice, anyone with a cheap guitar can be a better player by putting in the time. Buying a project forces you to put in the time, and is quite likely to provide a more capable machine for less money.
When thinking about used don't limit yourself to just Old American Iron. There are plenty of worthy Taiwanese, German, Spanish, and even Chinese machines out there. If you're willing to look past dirt, rust and old chips you may end up with a deal, the one thing I would avoid is something that is "restored". Often these machines are just painted to look pretty so the seller can make a quick buck. Alternatively it might be something wonderful but the seller has put so much into it that they think it's made of gold. These are good to go look at though because often the owners will give you lots of info on what the process was and maybe, just maybe they will like you enough to drop their price to something reasonable.
I've owned four metal lathes, the first one was a multi-function that wasn't worth the cast iron it was made from, I bought it new and was happy to sell it for less than half what I paid. The second was definitely "old iron" a 100-year-old Seneca Falls machine I got for $300 off Craigslist and still have today, I used it in my business and it more than paid for itself just cleaning up engine parts. The third was a rusty 6" Craftsman I fixed up because I really wanted to have something out here earlier this year, I paid $275 and put about another $300 into it. And now I have a 13x40 Bolton that I traded the Craftsman for straight across. It needs a lot of work but I like the process of fixing up and building machines, maybe even a little more than just making stuff with them....
Don't get wrapped up in trying to make sure your first lathe will be perfect, even a basket case has the potential to teach you more than you ever thought.
Cheers,
John