DH and I will be purchasing two new (or certified) cars pretty soon.

Does anyone have any tips or suggestions on how to get a great price on a car? I have heard all sorts of things over the years, like that you can get better deals at the end of the month, or if you buy in the winter, or if you finance (I have heard the opposite too, i.e., its better to pay in cash). Who knows??!!! So, what are some of the best ways to get a good deal on a car???

If it helps, DH is interested in a Jeep and I am leaning toward either a Volvo or a Buick.

TIA.