Ticket is a piece of paper to present upon checking in or boarding. You cannot board with out it. Booking your ticket earlier before the date of your trip enable you to save on prices and discount offers.
Online is the best source of finding good deals on plane ticket. There are tons of travel agent online that is willing to help and assist in finding good prices of tickets.
The first time I traveled outside the country, I went to travel agent and picked up my ticket. It took me long hours waiting for my priority number to be called. This is one of the inconvenient you will encounter when buying your ticket at the ticket office or travel agent office.
The last vacation we had, we bought the ticket online 2 weeks before. Found great deal and prices of ticket to Las Vegas so we opted to buy 3 plane tickets. To take advantage of the reward in buying a ticket, I click through at MyPoints where I am registered as member. I know that some credit cards have mileage points but you will get double reward if you click through other site that give rewards.
You can book your ticket online or at any travel center like orbitz, priceline, expedia, travelocity and more to get rewarded at MyPoints.