I actually have an entire reloading kit in a small tackle box. Its based around a Lee hand press, but if I take my time, I can roll my own way better than most factory loads.
My first reloading set up was $100, also a Lee, it is perfectly capable of churning out fine ammo. If I were to start reloading in serious volume, I'd upgrade to a beefier brand progressive, I came to the conclusion that unless I'm reloading for a very specific performance, like duplicating a carry load, or for accuracy, I'd rather spend my time on other projects.
I think of it this way. If I am shooting less than, say, 200 rounds a year of a particular load, I just buy it off the shelf.
On the opposite side of the argument, I have a friend that likes to shoot 458 Lott. He reloads because its too freakin' expensive, and he likes to experiment with various loads.
Getting back to your OP, I'd keep the 300 mag, and buy a nice lever action in 30-30. The two would complement each other, one for big game, and the other as a brush gun.