Flat price based on volume/Tier

Summary:

We have a requirement to calculate the price based on quantity/volume as follows;

If quantity is 0 to 50 then flat price of 100$, if quantity is 51 to 100 then flat charge of 150$, if quantity is above 100 then per 50 quantity rate should increase by 50$

e.g. if quantity is 5 or 48- price and amount for that line should be 100$..... if quantity is 60 or 99, price /amount should be 150$ (and not calculating like 60*150$)

now if quantity is 161 then... it's like up to 100, price is 150$ for remaining 61 quantity it should treat increment of 50, so 2 blocks (1 - 50, 2-11) ... so price should be calculated as 150$+50$+50$ i.e. 250$