Look for a sample pages online
Since you are going to have to pay a lot of money whenever you purchase bible study tools, try to find a website on the Internet first which has one or more sample pages which have been scanned in — sites like Amazon.com and Christian books.com have such a feature for many of their books. You can look at some excerpts and read what is there. You can do this without actually purchasing the book, so is an experience which is very similar to browsing through the book at your local neighborhood bookstore. After looking at those example pages you will be in a better decision to decide if you should spend the money or use your money to purchase something else.