To get you off on the right foot you might bookmark the following site,
The Los Angeles Silhouette Club "The Cast Bullet / Hunting Articles Of Glen E. Fryxell"
Also while your there check out the link in the upper right hand corner on Cast Bullets. Also there is a link to a PDF version of Glens book there which is available for download. If you have the resources print it out and put it in a small binder for quick bench top reference. It comes in handy.
A few things I would highly recommend getting are,
First and foremost a lead thermometer. If he has any in stock you can pick them up from NOE Molds for around $30 delivered, and he is a great fellow to deal with.
Second, start hitting the discount second hand stores like Goodwill and such, try and find you a 8-10 quart or so cast iron dutch oven or a decent thick bottomed SS pot with top if possible. With the SS don't get the thin ones which look like they were stamped out, get something that looks substantial. Last thing you want is a thin sided pot giving way loaded down with 50# of 600+ degree alloy. Even if you just go to Wally world and get one full price, you will be ahead in the game. Never melt down your raw material in your casting pot. This will leave all sorts of stuff in it that will come back to haunt you later on. Use the separate pot to do all of your initial smelting and any future blending of alloys. The only thing I WILL add to my clean alloy in my casting pot is a strip of tin solder to aid in fill out.
Third, don't even waste your time with commercial fluxes. Just head over to your local lumber supply or hardware store and see if they will let you have a bag or bucket of sawdust. IT will do anything you need down when cleaning and smelting your lead.
If you DO find a good supply of wheel weights, you will need a good straining spoon or dipper. I got one that has about a 1/8" wire mesh basket on it. IT has been by and far the best tool I have gotten and I don't even know where I picked it up from. It works equally as well dipping out the clips or another junk in the initial smelt pot, but also works great to smoosh the burnt sawdust down into, and around in the alloy when I flux.
As mentioned the Lee molds are a great buy for the price, and a good way to get started. I have around a dozen or so different ones. The 6 cavity are a little to get used to at first, but once you get them down you can dump 20# worth of bullets in a hurry. This is another reason for the thermometer, you will find that while working your mold there will be a certain temp when it all comes together and your bullets will fall out like rain and be perfectly formed. Write the temp down on the side, this way you know ahead of time where you need to be to get going with fewer throw backs.
I haven't thrown this one in, but will anyway. I and many others use a small $18 dollar or less hot plate for several things. Initially I got it to simply preheat my molds or to keep them up to temp while I was adding in more alloy. Some folks feel setting the mold on the top of the pot or dipping the corner in the alloy is good enough. What ever works for you. I also use it to warm up a small pan of lube to either dip or pan lube certain bullets, and I used it before White Label Lubes started selling their version of 45/45/10 tumble lube. Once I finish up with my current batch, I will for sure be ordering some of theirs.
By and far however of all of this, you need a goodly amount of lead. If you think a hundred pounds is enough, you shouldn't even bother with it. That is about enough to get your feet wet and find out if you like it or not. IF so, and your shooting at a place you cannot recover your bullets then you run out pretty darned quick. Just sayin. The raw lead stock pile is like primers, better to have enough than to run out and can't find any. Stock up if you have the chance. Worst case, if you don't like casting, you can always turn around and sell it easily.
One last thing, if you DO find this is something your really interested in, and want to get something that will make things so much easier on you, do a search over on Castboolits, for post on PID Controllers. This has been one of the best things I have added to my list of things that I really didn't think I needed. Now I don't want to be without it. Bottom line is for about $100 or so, you either build or purchase already built, a temperature controller for your Lee pot. It will bring your alloy up to what ever temp you set it to, and hold it within about a 10 degree area with no turning the knob as you pour to keep things even. Is it needed, definitely not, but is it something great to have and use, OOOHHH YEA.