I've been looking through https://www.reddit.com/r/InstacartShoppers/ and it seems as though my first week wasn't too bad in comparison to other new shoppers. There is potential to do much better of course, but also things could have been worse. It's mostly about taking the right orders, being good at the job is the second most important thing.
Outside of the USA, I know that $300 is an insane amount of money for 20 hours of work. Sadly, that won't even pay my rent here and I have "low rent" for my city. It's still going to help out a lot in terms of me being able to continue living the way I want to right now.