I agree that you should start out on a single stage press. Even if you go progressive later you will still use the single stage press. A lot of progressive owners (myself included) leave the progressive set up for a single cartridge that we use very much, like 223 or 45 ACP, or 9mm. Then load the ammo with smaller requirements and experimental loads on the single stage.
I started on a single stage Rockchucker in 1984 and did get two Dillon RL550bs which I load 223 & 45s on. All my Magnum loads are loaded SS, 308 Win, 45/70, 44 Special, 38 Special, and as noted, any 223 & 45 loads that are experimental. It's a good system and works well for me. I can also load 9mms and 500 S&W and any other rounds that my friends may want for a gun that I don't own. I just load on the rockchucker SS. I use my RC as much as my Dillons.
May be a good idea to not have your reloading room too specialized.