Bob: If you have a scrap yard close that you can call, ask them if they have any pure lead such as from a x-ray lab, lead sheeting from old roofs, plumbers lead, etc. It whould be about .20 to .25 cents a pound & as stated above, you can easily cut it with your thumbnail or slice an thin edge of Very easy with a pocket knife. Lead used for fishing is usally not pure lead & has allot of tin in it, as does wheel weights.
Keep in mind that fumes from melting lead ARE toxic & could cause health problems.
If I were you, I would just buy a 20# ingot & a mold & use a Coleman stove & melt a lil & try it first & see if you like it. I have hundreds of #'s of lead & dispise casting bullets & only cast the ones that are fairly expensive like the .58 cal & larger.
IMHO, you can't save any money casting small balls as with the cost of the equipment & price of materials & etc., you might break even if you shoot a lot & cast for 10 years. I had one feller recently tell me he bought lead & cast 2000 .36 cal balls & saved $10. by the time he was done. It only took him all weekend..... Personally I would rather shoot for an 3-4 hrs & pay $5 for a box of balls than spend a day casting them & tossing half of what I cast (flawed) back in the pot. Strange that when ya cast your own bullets, you expect them all to be perfect.... Most of the guys I know that cast balls just do it because they like casting & shooting them & saying they made them.
And some guys just love casting them & that is fine. I have one friend that casts hard cast bullets for HP rifles & it is amazing the accuracy he obtains with them. He casts bullets all the time (it seems) and just loves doing it. Everyone had their own druthers... I druther be building a rifle....