It seems to have changed? Apparently, getting a refund is no longer guaranteed [1].

Also, compare with Kindle, where you can download a sample of any book you like, and it just sits until you get around to reading it. Once you finish the sample, you can decide whether to buy it. I think that model is closer to free with in-app purchases than anything else.

[1] https://support.google.com/googleplay/answer/2479637?hl=en

Same with App Store. https://support.apple.com/en-us/HT204084