> transactionAmount stores a text value(on the front end) ex: $1,000.00
> 
> I would need to sum the values and then format them (number-format?).

You can convert the values to numbers using translate($in, '/,', '')

In XSLT 1.0 sum() will only total numbers actually held in nodes, not
computed numbers. There are several ways to total computed numbers:

(a) a recursive template that computes the first number, and adds this to
the result of applying itself to the set of nodes that excludes the first
one

(b) construct a temporary tree whose nodes contain the computed numbers, and
use sum() to total over them. This requires use of the node-set() extension.

(c) use the sum() function in FXSL

(d) use the saxon:sum(node-set, expression) extension function in Saxon.

If these all sound too difficult, then try XSLT 2.0.

Michael Kay
http://www.saxonica.com/