It costs less on tuesdays and wednesdays i believe and if you purchase online it is also a couple of dollars cheaper.
Prices go up the longer you wait. I looked online to come home in July it was 59 online then it went up to 106.00 when i got there to buy my ticket that was with in 2 hours of me getting there after looking online. They told me prices change every 30 minutes there
My understanding is 1 hour before departing. I'm guessing that if there is room on the bus and you don't hold the bus up there are probably exceptions. Good luck.
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