You should book early in order to get one of the $1 (plus booking fee) seats. At least one seat on every bus is $1 (plus booking fee) – these seats are the first to be sold.
Once the $1 (plus booking fee) seats are gone, they are gone.
Please note the system will automatically calculate the cheapest price for the number of people travelling – it does not make any difference if you book seats individually or together – you will get the same price.
