Individual Category Sales Total and Main Category Sales Total

I'm not sure that I understand how the Category Sales are calculated.
My guess is that the sum of the sub category prices is added to the sum of the category prices which works for Rim, Lug Nut, Head Unit and Rim.
Based on that guess:
1. The Parts column could be populated using: =IFERROR(INDEX(Table3[Sub category],MATCH(0,INDEX(COUNTIF(K$1:K1,Table3[Sub category]),,),)),"")
2. The Sub Category column: =IF(K2="","",SUMIFS(Table3[Price],Table3[Sub category],K2))
3. The Category column: =IF(K2="","",SUM(L2,SUMIFS(Table3[Price],Table3[Category],K2)))
Let us know if you have any questions.