If you’re of the easily confused variety, Bioware and Electronic Arts have released a subscription vs free to play chart detailing the amount of access those who choose to play Star Wars: The Old Republic for free will get.
The chart is very specific, giving restrictions in sets of threes. That is, three Flashpoints are allowed a week, as well as three Warzones and Space Missions. You can, however, buy a week pass to have unlimited access to these features until your week is up, and you go back to the free-to-play model. Restrictions also apply to inventory and cargo storage, as well as the amount of revivals from death on the field.
Hit the link to check out the chart for yourself, unless you’re intent on paying in full from the get go, then no worries!