How can I calculate total pricing based on multiple priicing & usage tiers
(IF Then or AND):

Usage - Price
0-50,000 = $1
50,001 - 150,000 = $.75
150,001+ = $.50

Example:

250,000 units

Need to automate the following:

50,000 = $50,000
50,001 - 150,000 = $75,000
150,001+ = $50,000

Total Due = $175,000