Chinese language 中文 漢語

I never used the free version that much, I found it too restrictive. I've been reading around 600 lessons so far, so I think I got my money's worth for sure. It provides a clear path and the app is really well designed. But that's not to say you can't find other reading material elsewhere, it depends on how much effort you want to put in. If you want really nice, but old, reader, I'd very much recommend John DeFrancis Chinese Reader series (Beginning Chinese Reader, Intermediate Chinese Reader, Advanced Chinese Reader) which is packed with Chinese. It's available on the web. It's really amazing and will with spaced repetition progressively introduce you to 1200 unique characters and 8000+ compounds.

Sinolinguas graded readers are also available on the web if you don't have the ability to support their work.

But for DuChinese, If you're a student you're eligible for a student discount. And I think they, similar to The Chairman's Bao and Skritter, do huge discounts during like CNY and stuff? You can always try emailing them and ask when the next discount will be, or maybe they might even give you a discount just by asking :)