Formula for Tiered Pricing and variable amount of transactions

Hey everyone! I'm new to the forum and looking for help solving the formula for inputing tiered pricing. The pricing is as follows

Transactions per month Monthly Price
Tier One 1-10,000 transactions $1,000
Tier Two 10,001-50,000 transactions $5,000
Tier Three 50,001-150,000 transactions $15,000
Tier Four 150,001-500,000 transactions $30,000
Tier Five 500,001-1,000,000 transactions $60,000

Depending how many transaction per month, there are 5 different tiers each with a unique monthly cost. The other hard part I have yet to figure out how to include is putting in the equation that will help determine how many transactions. As in two different cells, one for users, and the other for the avg. amount of transactions per month, which can be changed accordingly to determine outcome. Say 250 users doing 1 transaction or 5000 users doing 5 transactions.

Thanks so much for anyone that can help me out! Here is a link to a similar forum that didn't quite have the response I needed. http://www.excelforum.com/excel-form...d-pricing.html

Is this something that is of to much difficulty, that would be better served posting in commercial services?