Docs: prominently advertise free Graphana Cloud availability (#4399)

docs/sources/_index.md

@@ -17,3 +17,5 @@ metadata about your logs: labels (just like Prometheus labels). Log data itself
 is then compressed and stored in chunks in object stores such as S3 or GCS, or
 even locally on the filesystem. A small index and highly compressed chunks
 simplifies the operation and significantly lowers the cost of Loki.
+
+> **Note:** You can use [Grafana Cloud](https://grafana.com/products/cloud/features/#cloud-logs) to avoid installing, maintaining, and scaling your own instance of Grafana Loki. The free forever plan includes 50GB of free logs. [Create a free account to get started](https://grafana.com/auth/sign-up/create-user?pg=docs-grafana-install&plcmt=in-text).

docs/sources/getting-started/_index.md

@@ -4,6 +4,8 @@ weight: 300
 ---
 # Getting started with Loki
 
+> **Note:** You can use [Grafana Cloud](https://grafana.com/products/cloud/features/#cloud-logs) to avoid installing, maintaining, and scaling your own instance of Grafana Loki. The free forever plan includes 50GB of free logs. [Create a free account to get started](https://grafana.com/auth/sign-up/create-user?pg=docs-grafana-install&plcmt=in-text).
+
 1. [Getting Logs Into Loki](get-logs-into-loki/)
 1. [Grafana](grafana/)
 1. [LogCLI](logcli/)

docs/sources/installation/_index.md

@@ -4,6 +4,8 @@ weight: 200
 ---
 # Installation
 
+> **Note:** You can use [Grafana Cloud](https://grafana.com/products/cloud/features/#cloud-logs) to avoid installing, maintaining, and scaling your own instance of Grafana Loki. The free forever plan includes 50GB of free logs. [Create a free account to get started](https://grafana.com/auth/sign-up/create-user?pg=docs-grafana-install&plcmt=in-text).
+
 ## Installation methods
 
 Instructions for different methods of installing Loki and Promtail.