With Visitor Visa (subclass 600), you can visit Australia to tour the place or for business visitor purposes for up to three, six or 12 months. In case you hold the passport of a certain country, you can get the eVisitor (subclass 651) visa for free. Passport holders of a specific country can also get the Electronic Travel Authority (subclass 601) visa by paying a service charge of AUD20.
For those who travel frequently to Australia for a short duration to tour the country, visit friends or family, or for business purposes (such as making general employment/business enquiries, participating in a conference, doing business negotiations etc), Frequent Traveler Visa is the one they should apply for.