Translation:The book is expensive.
No, 이 and 가 can be used for both living and non-living things. Here's the difference:
이 is used when the subject ends with a consonant character.
For example: 물건 (thing) ends with a consonant ( "ㄴ" ) so we add 이 to it. Therefore: it becomes 물건이
가 is used when the subject ends with a vowel character.
Example: 차 ( tea ) ends with a vowel ( "ㅏ" ) so we add 가 to it. Therefore it becomes 차가