I don't lease, but when I looked into it for the helluvit not too long ago, it was actually appealing for the first time ever. The money factor was basically equal to a 0% interest rate, which is what you want...
Also, I wouldn't put money down on a lease, especially if you think there's a good chance you aren't going to buy it at lease end...
Keep in mind, the selling price of the vehicle is negotiable in a lease just as if you were buying it, so when they start talking money down, I would just say how about we take it off the price of the car instead, it's doable...
I don't know what brand you're interested in buying, but some have more wiggle room than others. Good luck, and I think you're off to the right start so far by walking away, cars are easily impulse bought, and that's where they really getcha...
Also, if you know the exact car you want, I'd do all of my negotiating by email, and maybe pick up the phone to solidify the deal once I got what I wanted. Reach out to every dealer within reason of travel to get the car, and expect some to not even respond, some to not budge at all, and some to give you a decent deal that you can start to work with, then once you have it, get the top 3 dealers to try and beat one another out. You may get lucky and one do it right off the bat, but at least you already have a baseline to go off of it sounds (I doubt that was the best deal by far, either...)
Good luck, I'm tempted to get a new whip myself soon, but medical bills (teeth), and wanting to add another rental to the portfolio have me limited on the idea atm...
It is an exciting time when you purchase a car you want though for sure, so I hope you find what you're looking for at a price acceptable to you...