Averaging over a table based on criteria not being met

I have a table that can't have headers (or I think I could use dsum for this, I have included headers in the example table for ease of explanation), I want to work out the average "price per" when bought or sold, but only if the row doesn't match a list of names.

So if I wanted to do this for all entries (rows) where items were Bought, but not if Origin was "SWAP" or "G COMM", I would look at the first row, see A it doesn't match "SWAP" or "G COMM", add C to a COUNT variable, and add B*C to a TOTAL variable. I would do this for all rows and at the end do TOTAL/COUNT to get the average "Price Per" based on how many were bought not matching my criterium.

So for that example, row 1 & 3 are bought rows with matching Origin criteria, ((185)+(173))/(5+3) = Average Price Per of 17.625

(A) Origin	(B) Price Per	(C) Bought	(D) Sold
CITIZEN	18	5
"	20		14
"	17	3
"	20		3
COMM	24		5
CITIZEN	19		2
SWAP	14	16
G COMM	0		4

Solution

FILTER the data as needed
get both the filtered columns using INDEX and calculate as needed

=LET(data,
  FILTER(B1:D8,
    A1:A8<>"SWAP",
    A1:A8<>"G COMM", 
    C1:C8<>""),
  priceper,INDEX(data,0,1), 
  qty,INDEX(data,0,2), 
  SUMPRODUCT(priceper*qty)/SUM(qty)
)