Casting lead slugs for your firearms can be a very educational and rewarding experience.
Back in my "young & dumb" days (late 70's), when money was a bit tighter than it is now, I went out & bought a double cavity Lyman 265 gr. .454 mold, dipper, a $3.00 cast iron sauce pan, and a used Lyman luber-sizer. Over a Coleman camp stove I cast up umpteen thousands of slugs for my Ruger Blackhawk and Thompson Contender (both in .45 Colt) out of mixed wheel weights and linotype metal. I had a ball doing this and really learned a lot.
After a couple of years though, when I started making a bit more money at my vocation, I suddenly came to the realization that I could walk into my local gunshop and buy a variety of cast slugs that were just as good as the ones I made for just about the same amount of cash, and a lot less time investment. This was especially true when you counted in all the time I spent canvassing tire shops and begging for wheel weights and in looking for used type metal.
While I had certainly enjoyed the experience of casting and shooting my very own bullets, it didn't take me long to come to the conclusion that I'd rather take some of those long, hot hours over a lead pot and exchange them for some much more enjoyable hours actually out at the range (or maybe even fishin').
If you just want the experience of casting bullets and the ensuing education that comes with it, by all means, go for it. If you are looking for economy of shooting, casting your own bullets can be a detour down a "wrong road".
Best of luck,