How do I rank values within groups ignoring blanks/zero according to its returned sequence?

Hi salfa_an 

Here are a couple of options:

1. Modify your original expression to ensure Cost <> 0 within FILTER:

Rank 2 =
IF (
    Table1[Cost] <> 0,
    RANKX (
        FILTER (
            Table1,
            Table1[Product]
                = EARLIER ( Table1[Product] )
                && Table1[Cost] <> 0
        ),
        Table1[Returned Sequence],
        ,
        ASC,
        DENSE
    )
)

 2. Rank over a table of distinct values of Returned Sequence, created using CALCULATETABLE:

Rank 3 = 
IF (
    Table1[Cost] <> 0,
    VAR RankingTable =
        CALCULATETABLE (
            VALUES ( Table1[Returned Sequence] ),
            ALLEXCEPT ( Table1, Table1[Product] ),
            Table1[Cost] <> 0
        )
    RETURN
        RANKX (
            RankingTable,
            Table1[Returned Sequence],
            ,
            ASC
        )
    )

Do these work for you?

Regards