Sign up for email and text alerts to Natchez shooters supply and target sports USA. You’ll have to buy the $100/yr plan at target sports to have a chance at buying ammo though. Another option would be to quit your job and go stand in line at academy every morning at 9am. Based on the secret Facebook groups these guys seems to be doing very well for themselves. I can often times know what was available at academy that morning within an hour of the store opening by their posts. Although I will say I was disappointed when I went into academy on Friday and saw their .223 lacquer coated steel cased ammo was selling for $16/20 and their 50 rounds of 22mag was selling for $40. I imagine the cat is out of the bag now and academy is marking their stuff up too just like everybody else.
Sig drops 9mm ammo almost every morning at around 3:40am CST. You gotta be on at 3:40 and keep refreshing until it’s in stock. Gotta be real quick as it’s only live for like 3 minutes or less before going out of stock. Was great before they implemented the 3 box limit but you can do multiple orders and pay separate shipping (comes out to something like .48cpr after shipping) Other calibers drop randomly throughout the week and have a 2000 round per month limit edit: clarification
Agree with the above posts. Find you / make yourself an online "list" of ammunition and firearms distributors based on what you're trying to purchase. Sign up on all of them for "in stock" notifications. Pounce when something comes in stock. Based on what your daily schedule is (w*rk, etc.) make a plan to troll pawn shops and gun shops. Things are showing up, in stock. Ammunition can be found reasonably inexpensive but you will no longer be able to take for granted that you can just walk in and buy a box or 2 of what you need. Watch the forum, people are regularly posting what and where things are in stock. "Ammunition in Stock" thread, and "Good Deals" thread are 2 ongoing active threads I'd watch if I were looking for ammunition. Use the "New Posts" and "Follow" functions on this forum to your advantage. There are many other forums similar to this one based on a specific firearm, I'd search & join those too. Many use the exact same software and so are easy to use, like this one.
Good luck and welcome to the forum.