Well, i imagine if you are looking at CHEAP bullets that can be used in 45ACP then you will be having a very hard time getting any atm. I had no problem getting 45cal 260gr and i could have gotten some 300gr bullets last time i was at the gun shop. 44mag bullets are also easier to find. Its not as commonly used for defense purposes. 458s would be another caliber less in demand atm.
MidwayUSA has the 45cal 250gr GoldDot/DeepCurl atm for $15ish per 50. Good bullet for lighter loads you said you intend to shoot.