Getting lead is not nearly so easy as it used to be but it can be done as Safari Hunt mentioned above. IF the shooting range you go to will allow it. As with most things in the world, restrictions are constantly being added to every aspect of our daily lives and I'm seeing ranges forbidding digging lead from the backstop. You can order clean lead from places like Rotometal and while far more expensive than free range scrap or lead from a scrap yard the Rotometal ingots will be a lot cheaper than commercial bullets. You can get away with pure clip on wheel weights for practically all handgun bullets and I've used them exclusively for the 32-20 up to 1,280 ft/sec, with no gas check, and had no problem with leading. But that's almost a moot point since clip on wheel weights are about all gone anyhow. I've been casting since the late 1970's when I was casting not only for my own shooting but to sell to a local shooting range and it pays for itself many times over. Very comforting to know you have buckets full of bullets on the cheap laying under your loading bench. And as EastTnHunter said, if you get good bullet fit and hardness you can load full power loads for hunting in a lot of the typical "woods deer cartridges" that operate around 2,000 ft/sec. What I like to do with those cartridges is to chose a bullet a little heavier than factory loads so you drop velocity down a bit and then load for full power. Some people are using loads considerably lighter than that and killing deer just fine too. Say something like 1,700 ft/sec. For hunting bullets a mix of 50% clip on wheel weights and 50% pure lead works pretty darned good.
Something that I never tried until just a few years ago is adding Tin to the alloy since I started as a broke college kid casting in my dorm room. (Try THAT nowadays and see what you'd get! )
Keeping cost at a bare minimum was a necessity back then but now I am willing to spend a bit more to get better bullets. Tin can be had from Rotometals for less than $20/lb and you just need 1% to 2% to get a very noticeable improvement with mold fillout among other desirable characteristics.
I assume you have found the castboolits.com website if you are interested in casting your own. I wish I'd had a resource like that back when I started as I had nothing but myself and my roommate to learn by doing.
I have noticed that most casting equipment has been sold out too. Gas checks even are gone except for the odd calibers and they are spotty as far as availability. I have 2,000 each in 22, 30 & 35 caliber but only 1,000 in 8mm, 44 & 45 caliber. For lower velocity practice loads you can shoot without them using "shotgun" powders to save money.