Remember that, in some cases, you will not be able to purchase single-day passes to South by Southwest. For example, the interactive festival requires that you purchase a two-day pass, as the demand to attend for networking purposes is quite high. Check your personal schedule to be sure that you will be free and available to attend all events during the two-day period before you purchase tickets, as they are generally non-refundable.
Book your hotel accommodations for your stay in Austin at the same time as you purchase your South by Southwest tickets. Official ticket vendors usually offer discounted rates for local hotels at the time of purchase, though quantities are often limited. The demand for hotel rooms in Austin will be very high during the week of South by Southwest, so it's best to book your hotel accommodations as early as possible, either before you buy your tickets or through an official ticket vendor as part of a package deal.
Read the official information provided by South by Southwest organizers on the conference website (see Resources below). Find out the dates that tickets go on sale and the approximate costs of each type of pass.
Investigate any presale offers available through official ticket vendors. Often, South by Southwest sponsors will offer ticket presales as a promotional move, allowing people on their mailing lists to buy tickets before the general public. Take advantage of these offers whenever possible, as South by Southwest tickets are usually in very high demand.
Check eBay for online auctions of South by Southwest tickets. Make sure that the seller is willing to send your tickets by express mail if you are buying the tickets very close to the date of the event. You will need physical copies of the tickets or badges to gain access to a South by Southwest event, so do not try to use an email exchange or written letter as your proof of purchase.