gistfile1.js

function dollabillsyall(strings, ...values) {
	return strings.reduce( function(s,v,idx){
		if (idx > 0) {
			if (typeof values[idx-1] == "number") {
				// look, also using interpolated
				// string literals!
				s += `$${values[idx-1].toFixed( 2 )}`;
			}
			else {
				s += values[idx-1];
			}
		}

		return s + v;
	}, "" );
}

var amt1 = 11.99,
	amt2 = amt1 * 1.08,
	name = "Kyle";

var text = dollabillsyall
`Thanks for your purchase, ${name}! Your
product cost was ${amt1}, which with tax
comes out to ${amt2}.`

console.log( text );
// Thanks for your purchase, Kyle! Your
// product cost was $11.99, which with tax
// comes out to $12.95.