@dp.message_handler(commands=['start'])
async def send_welcome(message: types.Message):
    await list_categories(message)


async def list_categories(message: Union[types.CallbackQuery, types.Message], **kwargs):
    markup = types.InlineKeyboardMarkup(row_width=2)
    markup.insert(types.InlineKeyboardButton(text='Прайс', callback_data='price'))

    text = f'Добрый день!\n\n' \
           f'Мой номер:\n' \
           f'+7-996-000-00-00'

    if isinstance(message, types.Message):
        await message.answer(text=text, reply_markup=markup)

    elif isinstance(message, types.CallbackQuery):
        call = message
        await call.message.edit_text(text=text, reply_markup=markup)


@dp.callback_query_handler(text='back')
async def test(callback: types.CallbackQuery):
    await callback.answer()
    await list_categories(callback)


@dp.callback_query_handler(text='price')
async def inline_kb_answer_callback_handler(callback: types.CallbackQuery):
    await callback.answer()
    markup = types.InlineKeyboardMarkup(row_width=2)
    markup.insert(types.InlineKeyboardButton(text='Назад', callback_data='back'))
    text = 'Тут прайс'
    await callback.message.edit_text(text=text, reply_markup=markup)