I knwo I am overlooking something but I just cant seem to figure out what it is to make what I want work.

In each record I have a field called Cost and then in my footer I have field called Total spent.

I want total spent to be the sum of every record's Cost field.

How do I do this?

You can create a summary field that sums up your cost field. If you want it for every record regardless of the found set, then create a cartesian 'X' join to the TO of the table that the field resides in.