Questions & Answers about این کتاب از آن مجله ارزانتر است.
How is the word for "cheaper" (arzan-tar) formed in Farsi?
Just like adding "-er" in English, Farsi adds the suffix -tar to the end of an adjective to make it a comparative. The base word for "cheap" is arzan, so "cheaper" becomes arzan-tar.
I learned that az means "from". Why does it mean "than" in this sentence?
You are right that az usually means "from"! However, when you use a comparative adjective (like arzan-tar), az is used to introduce the thing you are comparing to. So, az ān majalle means "than that magazine". You can think of it literally as being "cheaper from that magazine".
Why is the word ast ("is") at the very end of the sentence instead of after "This book"?
Farsi is a Subject-Object-Verb language, which means it generally puts the verb at the very end of the sentence. While English says "This book is cheaper than that magazine," Farsi structures it as "This book than that magazine cheaper is."
Do I need to use a connecting vowel (ezāfe) between in (this) and ketab (book)?
No, you do not. Pointing words like in (this) and ān (that) sit directly next to their noun without the ezāfe linking sound. You just say in ketab, never in-e ketab.