Desert Hound
DA
Not much apparently.I will concede that your knowledge is broader than mine because I have never known anyone who buys cheap ammo. it's likely to destroy your aim, your weapon, and your reputation.
Also-- in my limited experience, the reason for going to the range is to sight your weapon in so that you are more likely to get a first-shot kill. Using different ammo for the range and the field defeats the purpose.
Tournament shooters load their own rounds so that they will have confidence that every shot will be pretty much like all the others.
But what do I know?
You have not spent much time on the range, or just out in the desert/forest shooting for fun. If you had/have you will see people using inexpensive ammo all the time.
Cheap ammo doesn't throw off your aim. It isnt as accurate, but if you shoot right, you are going to hit right about where you are aiming.
Do you want to use it for hunting? No. It is the wrong type of ammo. Do you want to use it for competition? No.
Will it help you become a better shooter? Yes.
Will it damage your rifle? No.
Cheap ammo is generally dirtier and so you have to clean your rifle better/more frequently.