Questor,
You would be hard pressed to find a better value for your money than a MEC 600Jr. They run a little under $100 new and a little over half of that used. You see them a lot on eBay.
I started loading Shotshells with a MEC 600 Jr. in 20 Gauge and 30 years later, it's still working fine.
Get yourself a copy of the Lyman Shotshell Reloading Handbook 4th Edition before you start loading and read the front of it closely. This is the part that tells you what to look for, what to do, what not to do and so forth. The rear 80% of the book is all loads you can use.
Other than the MEC press you will need powder, primers, shot and possibly powder bushings for the MEC. Whether or not you will need them will depend upon the powder you use and how much of it. If you buy new, they come with 3 bushings...some of the more commonly used ones. You can also get new bars that throw larger amounts of shot than the one that comes with the MEC. I believe the one that comes with it throws 7/8 oz. of shot and you can get them to throw 3/4 oz., 1 oz or 1-1/8 oz. or whatever quantity you want to use.
Since you already reload metallic, I know you must already have a scale and are familiar with its' usage, so we won't go there.
Have fun,
Ka6otm