def merge_lists(l1, l2, key):
  merged = {}
  for item in l1+l2:
    if item[key] in merged:
      merged[item[key]].update(item)
    else:
      merged[item[key]] = item
  return [val for (_, val) in merged.items()]

f1 = [{'name': 1, 'price': 2}, {'name': 3, 'price': 2}, {'name': 2, 'price': 4}]
f2 = [{'name': 1, 'time': 100},{'name': 2, 'time': 100}]

f3 = merge_lists(f1, f2, 'name')
print (f3)