Basic AVERAGEIF/ whatever you suggest question

Hi guys

I regularly sort through data such as that below. LEt me put it into context for you. 1, 2 and 3 are products. Within 1, 2 and 3 are 4 variants (colour variants maybe). Now, the second column is the price of each variant. I want all the prices to be the same for the same product. I want a way to see immediately that theres a variation in price within the 4 lines of product 1, 2 or 3 etc.

Right now I use a subtotal table pasted into a backsheet. It's dreadful and I'm sure averageif would work if I knew how to make it work!

1 20
1 20
1 20
1 21
2 15
2 15
2 15
2 16
3 8
3 8
3 8
3 8

I was thinking along the lines of an equation that averages just the 4 cells where "1" is in A1:A10000 or similar.

Any help much appreciated

Many thanks.