Do you need to buy tickets ahead of time to go on the observation deck? How much a ticket for 2 people?

You do not have to purchase tickets ahead of time although that is an option 2for$30

Where do you get the 2 for $30 tickets?

See the different package options https://web.ticket.spaceneedle.com/

You do not need to purchase tickets ahead of time, although I would recommend doing it, as it reserves a specific time window for you, and the lines are then much shorter.

You can purchase tickets on site. $22

They do have a limited number and do sell out at times. Happened to us and we had purchased the City Pass bundle.

You buy at the gate

You can get tix using one of the machine. It fairly straightforward and the line was not too bad for me when visiting.

I just inquired yesterday about the adult price per ticket an it was around $45 dollars.

Now the price si $35 dllrs and need presente your complet vaccine covid