Calculate difference between Min. & Max

Hi all,

I have a dataset that shows orderlines per row. Similar to this table:

I am trying to create a visual table that shows Min. Max, Avg Price and the dif. between Min & Max.

Question / Help Request:

I can easily create the Min. Max and Avg. Sales Price, but I can't create the formula for dif. between Min. and Max.? anyone can help?

It needs to evaluate the row with the minimum sales price for a specific item and compare it to the same item just on the row with highest sales price.

Dif. between Min. Max = "Maximum Sales Price - the Minimum Sales Price" 

I already have the Sales Price Column, so i just use the inbuilt function for Min. and Max Sales Price:

For the Avg. Sales Price i use this calculation:

Avg. Sales Price = SUM(InitiativeMonitor_table[Turnover (DKK)])/SUM(InitiativeMonitor_table[Qty])