# assuming file with $100\n$200\n$23\n$50 etc.
  linenum_vals = []
  with open('numbers.txt') as input_file:
      for i, line in enumerate(input_file):
         try:
             linenum_vals.append([i, float(line[:-1][1:])])
         except ValueError:
             print("Not a number value on line", i)
  
  total = 0
  for i in linenum_vals:
      total += i[1]
  
  half = total/2.0
  
  for p in range(len(linenum_vals)):
      if linenum_vals[p][1] == half:
          print("Half of total found on line", linenum_vals[p][0])
          break
      else:
          if linenum_vals[p-1][1] < half and linenum_vals[p][1] > half:
              print("Half of total in between lines", p-1, p)
              break
          else:
              if p+1 != len(linenum_vals):
                  if linenum_vals[p][1] < half and linenum_vals[p+1][1] > half:
                      print("Half of total in between lines", p, p+1)
                      break
          print("Half of total wasn't found in the file.") # probably because the list of values isn't in order