Welcome to the forum sailorman!

I'm in Canada, so the market and pricing here are quite different. That said, I would concur that buying at the end of the month is a good idea, when everyone is typically trying to make or exceed their sales quotas. If you can combine this with a day when it's bad weather, that's an extra bonus because customer traffic will be poor so they'll both have more time to spend with you, and be more hungry for a sale.

You may already know this, but to get the best deal, you want to separate the "shopping" and "buying" phases. Don't mix up your test drives and investigations of what features/packages you want, with negotiating numbers. Take your time determining exactly where everything fits for you (absolutely MUST have, would be nice, or don't need it), and defer getting the best price for another time. You may even want to warn the salesmen "I won't be buying today, but any help you can provide won't be forgotten when I'm ready." Try to go to the same salesperson on repeat visits because this makes them invest more time in you, which translates into them wanting to get paid for it somehow later ... they're more hungry to close any deal.

So before you get to the "buying" phase, do all your homework. Contact several dealers (if possible) ahead of time, and get a feel for the dollar range within which they're willing to sell. During this phase, be polite but firm and hold fast to your "we can agree to disagree" demeanor. These preliminary skirmishes are designed (by them) to increase profit by telling you your purchase price expectations and anticipated trade-in value are unrealistic.

It can be helpful to practice how you will deal with them, ahead of time. For example, something like, "I'm afraid that's what I've budgeted, but if you can't do it for that, I understand. I really want this car so I may just have to wait a while longer. Thank you for considering my request. If anything changes, I'll be back in touch."

This helps you stay firm and explains why you can't bow to their demands (no matter how reasonable), while letting them know you're still a good prospect ("I really want this car"), keeping things polite and leaving the door open for contact in future, if in fact you determine this is the best place for you to deal.

As always, doing a cash deal with no trade-in value to cloud matters is best, but I realize that's not always possible.

Oh, and above all, remember: They sell more cars in a week than you'll buy in your lifetime. By definition, they're better at this than you are, so you need to make up for it by being prepared and firm!!

Anyway, I've probably said too much already, so post back with more questions if you'd like more!