How to determine contribution to average?

Question

I have a dataset like:

13,a,b,c,d,e
32,b,d,x,y,z
54,g,h,r,w,p
04,a,b,c,d,x
...

Basically, the first number is the cost of all the components (named the letters of the alphabet) after that. I have many datapoints like this, so I have very sufficient coverage usually of any component with pretty distinct other component set.

I was wondering if there were any methods I could apply to extract the average cost of component 'a' by teasing it out of the average data. Basically, I'd like something like this after:

a: 3
b: 12
c: 3
d: 4
...

I