allInputs.value //equals $45 and
allInputs.value // equals $70
allInputs.value + allInputs.value = "$45$70"
You can use
"$" + (parseInt(allInputs.value.substring(1)) + parseInt(allInputs.value.substring(1)))
substring method, will get rid of the $ sign, and
parseInt will convert it to a number. You need that, because if you do not use that it will concatenate the values as strings. Note that i put another set of brackets to sum the numbers. That is because, when the interpreter sees the "$" it thinks it should concatenate strings. But we want to sum the numbers and then concatenate the sum with the "$" string.