SumIf & Return Specific Values

Here's my problem. Lets say I have 10,000 rows of data and I want to know if within those 10,000 rows of data there is a combination within the cost column that equals a specific number (x = 3,115.84). Then if this specific number is found I'd like to return the ID # that is related to each row where the cost is used to get back to the specific number.

I've attached a sample file that may explain my question a little better.

This has stumped me for a while. I don't really think SumIf is the correct formula for this but I counldn't really think of how to summarize this question. Any thoughts?