The Stockholm public transportation system is run by SL and you can find many details on their website but here is also a summary and what tickets are available and how to plan and search for connections.
These tickets are enough to get you to and from the Arlanda and Bromma airports too, even though there are fast options at higher prices too for those connections.
| Validity time | Normal | Reduced |
|---|---|---|
| 75 minutes | 42 | 26 |
| 24 hours | 175 | 110 |
| 72 hours | 350 | 220 |
| 7 days | 455 | 290 |
| 30 days | 1 020 | 650 |