You can change the formatting to display it that way
Select the field and choose format --> number
Are you trying to use this value in a text expression like: "Your total cost will be $" & table::Field ?
I keep thinking there's a simpler way, but the following should work:
"Your total cost will be $" & let ( x = table::field; Case (int(x) = x, x & ".00"; int(x * 10) = ( x * 10 ) ; x & "0" ; Round(x,2) ) )