docs: Add synthetic start event (#1915)

The docs for synthetic start event. 

Related to the PR: apify/apify-core#22673.

---------

Co-authored-by: Matej Hamas <[email protected]>
Co-authored-by: Michał Olender <[email protected]>

Author: 3 people

sources/platform/actors/publishing/images/apify-actor-start.png

@@ -18,6 +18,12 @@ PPE lets you define pricing for individual events. You can charge for specific e
 
 The details on how your cost is computed can be found in [Example of a PPE pricing model](#example-of-a-ppe-pricing-model).
 
+:::tip Additional benefits
+
+Actors that implement PPE pricing receive additional benefits, including increased visibility in Apify Store and enhanced discoverability for users looking for monetized solutions.
+
+:::
+
 ## How is profit computed
 
 Your profit is calculated from the mentioned formula:
@@ -77,71 +83,36 @@ When using browser automation tools like Puppeteer or Playwright for web scrapin
 
 :::
 
-### Charge for `Actor start`
-
-Charge for `Actor start` to prevent users from running your Actor for free.
-
-<Tabs groupId="main">
-<TabItem value="JavaScript" label="JavaScript">
-
-```js
-import { Actor } from 'apify';
-
-const chargeForActorStart = async () => {
-  const chargingManager = Actor.getChargingManager();
-
-  // Don't charge the "Actor start" event again after Actor migration
-  if (chargingManager.getChargedEventCount("actor-start") === 0) {
-    await Actor.charge({
-      "eventName": "actor-start",
-    });
-  }
-}
-
-await Actor.init();
-
-const main = async () => {
-  await chargeForActorStart();
+### Use synthetic start event `apify-actor-start`
 
-  // Rest of the Actor logic
-};
+This event is automatically charged by the Apify platform when an Actor is started or resurrected.
 
-await main();
+Users of your Actor are charged one event for each GB of memory used by the Actor (at least one event per run). We _strongly_ suggest setting the price of this event to $0.0001 to remain competitive in the Store and attractive for your customers. If you define this event, you also save 5 seconds of Actor runtime from each Actor run, which won't be deducted from your payout profits.
 
-await Actor.exit();
-```
+:::note Automatic charging of synthetic start event
 
-</TabItem>
-<TabItem value="Python" label="Python">
+You must _not_ manually charge for the synthetic start event (`apify-actor-start`) in your Actor code.
 
-```py
-from apify import Actor
+If you attempt to charge this event yourself, the operation will fail.
+This event is _always_ charged automatically by the Apify platform whenever your Actor starts or is resurrected.
 
-async def charge_for_actor_start():
-    charging_manager = Actor.get_charging_manager()
+:::
 
-    # Don't charge the "Actor start" event again after Actor migration
-    if charging_manager.get_charged_event_count("actor-start") == 0:
-        await Actor.charge(event_name="actor-start")
+#### Synthetic start event for new Actors
 
-async def main():
-    await Actor.init()
-    
-    await charge_for_actor_start()
+For new Actors, this event is added automatically as you can see on the following screen:
 
-    # Rest of the Actor logic
+![New Actor - synthetic start event](../images/apify-actor-start.png)
 
-    await Actor.exit()
-```
+#### Synthetic start event for existing Actors
 
-</TabItem>
-</Tabs>
+If you have existing Actors, you can add this event manually in Apify Console.
 
-:::note Actor migrations and charging
+#### Synthetic start event for Actors with start event
 
-Actors can migrate between servers during execution, which restarts the process and clears memory. When using PPE pricing model, avoid charging the start event multiple times after a migration by checking your charging state.
+Your Actor might already have a start event defined, such as `actor-start` or another variant of the event name. In this case, you can choose whether to use the synthetic start event or keep the existing start event.
 
-:::
+If you want to use the synthetic start event, remove the existing start event from your Actor and add the synthetic start event in Apify Console.
 
 ### Charge for invalid input