It's not easy to find places to read Star Wars comics for free legally. Sometimes, there could be promotions or limited-time offers on official comic platforms, but it's not a common thing. I'd recommend looking for discounted subscriptions instead.
Star Wars wasn't initially based on comics. It started as a cinematic concept that later expanded into various forms of media, including comics. These comics often expand on the existing Star Wars lore and characters.
Star Wars comics can be canon. They're part of the larger Star Wars narrative. But it's important to note that the determination of canon can change over time and based on the decisions of the Lucasfilm Story Group.
Sure. There are several Star Wars comics that are considered canonical. They contribute to the overall lore and add depth to the franchise. Some of them explore events and characters not covered in the movies or TV shows.
Sorry, I don't have a definite place for you. Maybe do a search on popular search engines, but be cautious as many free sites could be violating copyright laws.