The price 45 EUR is for only one package. If you want to order more packages, just order more pieces for how the number of months you want to order. Beside the book, you can expect also extra.
If you will not be satisfied with the content, there is two weeks of return policy, so just send it back and the full amount will be refunded. OK, the return shipping will not be refunded, but otherwise the whole amount will be refunded.