Great info here already posted by the others. Gotta watch that Beagle fella though, he likes to make "pretty" bullets..
Seriously all of them have great advice and they can all pour up a great bullet. If I didn't kid ol Beagle he might think I was mad at him.
Me, well I got into this WAY later than I should have. I have been shooting since I was a snot nosed kid, and just seemed every time I messed with cast bullets I ended up with a mess on my hands. Sort of soured my taste for them I guess. Well up until a few years back that is.
I started off pouring hot lead into 4,6, and 8oz surf fishing weights and progressed into the 1-2lb ones shortly thereafter, to hold my bigger baits solid in the surf while shark fishing. For al lof this I quickly picked up one of the Lee 4-20 pots which served me well on the lighter weights, but for the bigger ones I had to modify it. I used some 1/4" SS tubing to replace the upright rods and a piece of 2x2 square tubing to raise up the back end. Been that way ever since and works great. The biggest thing about a Lee bottom pour is putting and keeping clean alloy in it. If you get trash in there it WILL plug up the spout, but it only takes a finishing nail and pair of pliers to get her back up and running, least until you get through whats in the pot and can clean it up good.
As for the molds, I started off using the Lee 6 cavity right from the start. I was only going to pour for my 454 and since I liked to shoot it so much it only seemed logical to pour as many up in as short a time as I could. It only takes about 20 minutes to empty the pot with those 300gr chunks. The biggest issue most have with the 6 cavity molds is trying to pour all 6 cavities at once then cut them off before the mold has really heated up. They aren't harder to use than the others IF you get them up to temp before you really start pouring hard. Usually if you simply take your time and pour the first two cavities pretty fast the end will heat up. Then once your having to wait on the sprue to cool on those add another one, and repeat. Soon enough your pouring all six and rolling right along.
Personally I would suggest you get the Lee pot if for no other reason it is easy to control your pour height, not that you can do so with a ladle. I would also throw in that a thermometer should be your next tool so you can keep your alloy as consistent as possible on the temp. The hotter it gets the hotter your molds will get, and the smaller and lighter your bullets will be.
On cleaning your alloy, never put it in your pour pot. Always smelt it down in a separate pot where you can flux it and clean it up before putting it into your ingot molds or using it to pour bullets. The best thing for fluxing is sawdust, usually pine or oak. Either one will give you a lot of carbon which when stirred into the alloy will blend the things which need blending, and render out the stuff that need rendering. This will all come to the top as you stir. Also while doing this it is important to keep the temp in the 675-700'ish degree range to try and keep any unwanted zinc from becoming a part of and possibly ruining your new batch of alloy.
For additional information on what to do, and how to do it, get over to Castboolits and read up in the stickies. That should take you most of a couple of months in of itself. Then in between there and your head spinning from information overload, head over to
www.lasc.us and read through and download the articles and such from there which will guide you through to great bullet making from start to finish.
As with anything else the old saying, you get what you pay for, definitely comes into play when your buying molds. That isn't to say Lee doesn't put out a decent mold for the money, far from it. But once you have your feet under you, you should look into investing in one of the customs, from Accurate, NOE, MP, NEI or similar. Also Lyman, RCBS, Seaco, and others put out some great molds, but, and this is only my opinion, the first list there is where I will be spending my money on any new molds. I have some of all the others I purchased used simply to try out. Some worked some didn't. But just getting into things you simply cannot beat the Lee prices and learn with those then move on up. Sort of like learning to drive in a Vette verses an ol beater. It can be done, but once you've learned all the basics and "to do's" and "not to do's" in the beater, now how much more do you appreciate that new Vette when you slip in behind the wheel?
Hope that helps.