I started reloading a few months ago for same reason as yours, in my case for a 2.5-inch chambered Army Navy 20 gauge. Agree with getting a MEC 600JR in your gun's gauge. Ebay is a good source. Although I did buy a short kit to allow fold crimping 2.5-inch shells, I have not used the short kit as I am roll crimping instead. Roll crimping has several advantages: It is how shells were closed when guns were routinely chambered at 2.5 inches. You can use cut down 2.75-inch hulls more easily, as roll crimping doesn't use as much hull length as fold crimping. You don't have to worry as much about getting stack height just right for a perfect crimp.
BPI has some useful manuals. I have and find useful the following: Advantages Manual Shotshell Load Encyclopedia, Cheddite Manual, Loading Shortened Hulls, Roll Crimping Your Shells. Roll crimping requires a gauge-specific bit for a drill, a shell vise, and a shell cutter, all three of which can be had for about $100 from BPI or Precision Reloading.
Since you already reload you probably already have an appropriate scale.
Straight wall hulls such as Cheddite or Fiocchi are preferred for 2.5-inch shells, as they have a little more room than Remington or AA hulls. There are a lot of recipes for short roll crimped shells in the above-mentioned publications. If you have to substitute components due to the current problems with component availability, it isn't a bad idea to have your shells pressure tested (not necessary if you are able to go strictly by published recipes). Precision Reloading offers load testing for pressure and velocity for $40 for a 6-shell string, or $25 per string if more than one string.
As for the MEC press, to use it to load powder and shot you will need a variety of powder bushings and charge bars for different shot charges (3/4 oz, 7/8, 1, 1 1/8, etc.). HOWEVER, I suggest not using the press to drop shot and powder at first, but rather weigh the shot and powder for each shell at first, and after you have established, by patterning and/or pressure testing, what you will need, then order accordingly. Actually, if you weigh your powder and shot for each shell, and roll crimp, the press will be used only for the de-prime/re-size station and the re-prime station.
Good luck, have fun, and be safe!