Extracting data based on range

I have a table for the number of products sold:

Product Sold
2020 2021 2022 2023
A 1 3 5 6
B 3 5 7 9
C 1 3 4 5


I have another table that calculates the cumulative product sold

Culmulative Product Sold
2020 2021 2022 2023
A 1 4 9 15
B 3 8 15 24
C 1 4 8 13



I have a price table based on # of product sold:

Item Price
<10 5
<20 3
<30 2
<40 1


What equation should I write to get the cost price of the product based on cumulative data? Basically, as the cumulative product for category A is less than 10 till 2022 the multiplier price is $5 but in 2023 as the cumulative product is more than 10 the multiplier is $3.

Cost
2020 2021 2022 2023
A 5 15 25 18
B 3 5 7 9
C 1 3 4 5


Please know that the actual data set has a price multiplier for multiple range and the number of products sold is in million. The above is just a sample.

Apologies. Attached is the template.