This is the whole list in one place. The screens where you ask for something do not quote a price on the spot — your balance is on Account → Usage, and this page is what it is spent on.
Asking a question
| Credits | |
|---|---|
| About a passage you selected | 7 |
| About everything you marked, or one tag | 7 |
| About the unit you are reading | 15 |
| About the whole course | 50 |
Asking against your own marks is priced as a passage question, however many marks it covers.
Summaries
| Credits | |
|---|---|
| Summarise a unit | 18 |
Practice tests
Priced by length, from 5 questions to 100, in fives.
| Questions | Credits |
|---|---|
| 5 | 25 |
| 10 | 35 |
| 20 | 60 |
| 40 | 105 |
| 60 | 152 |
| 100 | 246 |
The sizes in between are priced in between. Longer tests cost less per question, so one 20-question test is cheaper than four 5-question ones.
Free
| Reading any course you have added |
| Highlighting, and reading your marks |
| Reading an answer, summary or test again |
| Retaking a test you already made |
When prices change
If a price ever changes, it changes going forward. Anything you have already been charged stays as it was charged.