Express bus to Nagano from Ogizawa

I will be on the Tateyama Alpine Route end Oct on a weekday. I start at the Toyama side.
I have 2 questions.

Is it possible to buy the Alpine Route ticket on the day itself?
and
Where do I buy the express bus ticket to Nagano from Ogizawa and how much does it cost?
Thank you.

Is it possible to buy the Alpine Route ticket on the day itself?

Yes.

Where do I buy the express bus ticket to Nagano from Ogizawa and how much does it cost?

At a ticket window at Nagano Station or on board of the bus.

The cost is 3700 yen:
https://www.alpico.co.jp/en/timetable/tateyama_kurobe/r-nagano-omachi-...

Thank you for your reply.
But I am taking the bus from Ogizawa to Nagano, so where can I buy the ticket from in Ogizawa. Can I use card to pay or do they only accept cash?

If I buy the ticket on board the bus, do I need to use cash?

Thank you.