A "good kit" is something I'm going to go over in class, but here is an overview.
First off, figure your budget. Reloading uses tools, and like any tools, you can get the job done with cheap stuff, or you can make it easier on yourself, and get the job done faster with better tools.
Old timers will tell you to buy a single stage press to learn the basics on, then upgrade to a progressive press. IMHO, if you're willing to put in the investment, a good progressive press (which can churn out 350+ rounds an hour when setup correctly and a competent monkey pulling the lever) can be setup and used as a single stage. You don't have to have everything going at once, just load up one die, and do each step as a single stage. Then, once you get your head wrapped around what each stage does and how to perfect that stage, load up all the dies and start making bullets!
On the flip side, a single stage press can be had as a full blown kit for less than the progressive press alone
! And honestly, *everyone* needs a single stage press if they are doing precision rifle ammunition. So eventually, you'll have *both*. It just depends on what your budget is and how much you're willing to pay out up front.
Right now Midway USA has the RCBS Rockchucker kit on sale. Most old timers have the Rockchucker as their single stage press...unless they are into super-precision rounds, then they probably have a super-precision single stage press (some even hand made!)
Another great bang for the bluck is the Lee press kit. Lee is sort of the Hyundai of presses. Cheap, and gets the job done.
For progressive presses...well, it's almost like asking what oil is the best to car guys. It can get kind of heated as some people are die hards (usually the Dillion guys aka Blue Kool-Aid - Think Harley guys talking down to sport bikers).
I love my RCBS Pro 2000 press, but having played with a couple of the Hornady Lock N Load progressive presses with all the bells and whistles...holy shit they make some great hardware for the money and it can press much faster than my RCBS press. And if you're a Ducati riding, Starbucks sippin baller, there is always Dillion Precision presses. If I were to go balls out progressive press today, the Hornady LnL would be the one I'd get:
That said, you can get a good progressive press without all the bells and whistles, buy a good digital scale, some dies for the caliber you want to reload, and a few basic accessories to prep the brass, and probably get started for about $600.
As for how quickly pressing your own bullets will pay for itself...figure you can save 40%-60% depending on the caliber and current prices, and considering you get better deals when buying the components in bulk. Just calculate out how much you spend, how much you'll save, and how much you plan on shooting each month...and it's easy to figure out when the press starts paying for itself.
Back in 2000 when I got my RCBS Pro 2000 press, I dropped about $1000 into hardware and figured I had it all paid off in less than 3 years of *casual* shooting. And back then, bullets were considerably less than they are now. The cost of presses and accessories has hardly gone up at all, so you'll break even much sooner now, especially if you're doing more than 9mm (typically the cheapest bullet cost per round).
So yeah, that was a bit longer then I wanted it to be, but that's the summary. Figure out what you want to spend, figure out which caliber you want to start with (pistol calibers are easier), and we can dial you in more specifically.