Using a SUMIF formula and not sure if this is correct

I have about 100 rows of data in column A and values against each in B. I was trying to construct a SUMIF formula to pull specific names out of Column A and sum the totals from B. I can get the formula to work if I just ask for one criteria but when I add multiple I gets errors.

=SUMIF(A1:A4,"=Product",B1:B4) - This works if I am just looking for products but when I try to also bring in totally Products, Sales and distribution into this formula it errors.

Any help would be appreciated.

cheers
Barry

Please post sample file with correct answer that you need.