Multi level pricing

[erratumsolutions]

Discussed in #74

^{Originally posted by zycabathware May 29, 2022}
We need an option to set different pricing per item. Something like, Price A, Price B etc
So that for each item we can set different prices and then we can assign Price A to a customer, so he will always get the Price a benefits

From another customer:
We are also looking for something similar. But we need it as per quantity.
Say like, for 1-5 quantity, INR 100, for 6-13 qty, INR 90, above 13 INR 87 like this