chore(billing): Add more content to spend notifications

docs/product/alerts/notifications/index.mdx

@@ -8,7 +8,7 @@ Sentry sends you notifications regarding workflow activities, [release deploys](
 
 - [Workflow](#workflow-notifications): Activity involving user actions and state changes on issues. This includes activities such as issue resolution, assignment, comments, and regressions.
 - [Deploy](#deploy-notifications): When a release you have commits on is deployed.
-- [Spend](#spend-notifications): When you're getting close to spending your reserved volume, your quotas are depleted, and/or your on-demand budget is being put to use.
+- [Spend](#spend-notifications): When you're getting close to spending your reserved volume, your quotas are depleted, and/or your pay-as-you-go budget is being put to use.
 - [Weekly Reports](#weekly-reports): A summary of your organization's Sentry activity.
 
 You can manage these notifications in **User Settings > Notifications**.
@@ -49,14 +49,35 @@ Sentry sends deploy notifications to users who have committed to the release tha
 
 ## Spend Notifications
 
-By default, Sentry sends spend notifications to all owners of an organization when:
+By default, Sentry sends spend notifications to all owners and billing members of an organization when:
 
-- 80% of the organization's reserved volume (for errors, transactions, and/or attachments) has been depleted.
-- The entire reserved volume and any on-demand budget for a category (such as errors, transactions, and/or attachments) has been depleted.
-- 80% of the organization's on-demand budget has been used.
+- 80% of the organization's reserved volume (such as errors, spans, and/or attachments) has been depleted.
+- The entire reserved volume and any pay-as-you-go budget for a category (such as errors, spans, and/or attachments) has been depleted.
+- 80% of the organization's pay-as-you-go budget has been used.
 
 Learn more in the [full Quotas documentation](/pricing/quotas/).
 
+### Configuring Spend Notifications
+
+Billing or owner members can set up their notification thresholds by going to: **Settings > Subscriptions > Notifications**.
+
+![Notifications tab of Subscription settings page](./img/subscription_notifications_settings.png)
+
+From here, you can set up customized notification thresholds for your organization:
+
+- **Subscription Consumption**: Set the percentage of the quota usage threshold(s) that triggers a notification.
+- **Pay-as-you-go Consumption**: Set the percentage of Pay-as-you-go usage threshold(s) that triggers a notification.
+
+### Personal Spend Notifications
+
+If you are an owner or a billing member of an organization, and if you wish to customize how you receive spend notifications, you can do so in your user's notification settings page:
+
+1. Go to your user setting's notifications page: https://sentry.sentry.io/settings/account/notifications/
+2. Click on the cog wheel icon on the **"Spend"** row.
+3. This should take you to: https://sentry.io/settings/account/notifications/quota/
+4. From here you can either enable or disable receiving spend notifications by delivery method (e.g. email or Slack), or by organization.
+    - **NOTE: **The configuration of the spend notifications thresholds (e.g. receive notifications on at least 80% quota consumed) is done on the Subscription settings page of the organization. See above on how to configure this.
+
 ## Weekly Reports
 
 Sentry sends weekly reports every Saturday, by email. Reports contain a summary of your organization's Sentry activity over the last week.