When I became interested in saving money on my grocery bill, I purchased both this book and Mary Ostyn's book, and have read them both thoroughly. Honestly, you will be better off just getting Mary's instead.
Before I get to the negatives, I'd like to state the few positives. I give props to Erin first for recognizing that Americans eat too much, and second for working vegetables into every meal. The reviewer who said that this book is overall unhealthy is exaggerating a little. Yes, she uses regular ground beef, but processed foods are in only a few recipes and frozen vegetables are still vegetables (and she does encourage growing your own). Both Erin and Mary emphasize eating less meat and offer vegetarian meal options. Erin does mention the use of a price book, but Mary does to a MUCH more thorough extent.
Now the other stuff...
The tips in this book are all commons sense-stock up when it's on sale, match coupons to sales. You don't need a book to tell you that. Every positive aspect of this book can be found in Mary Ostyn's book Family Feasts for $75 a Week, and you'll find lots of other information as well. Erin gives an ingredient by ingredient price breakdown in every recipe, which is a good concept, but the problem is that price can vary largely depending on where you are. There are some items that she's apparently been able to find at prices that I've never, ever seen anywhere I've been, and I'm a very price-conscious shopper. So, a lot of her "$5 meals" I would not be able to make for $5. Also, she groups the side dishes right in with the main course, including the price tag, so if you want to change up some of the main course-side dish combos, you're going to alter the price (and if you're not eyeballing the price, there's no reason to buy this book at all). Speaking of side dishes, this book has a lot of "bare" vegetables, so if you have taste buds and like to put a little salt or butter on your veggies, that's going to affect the price.
Some people have expressed concern over the portion sizes in this book for a family of four. Erin has two children, and they are both very, very young, and thus probably consume much less than a teenager or adult. If your two kids are teenagers, most of these recipes will have to be adjusted quite a bit, and thus make the final price much higher than $5 dollars. For that reason, I don't like the concept of putting a dollar value on the meal as a whole, but rather a dollar value on a "per plate" basis. Mary states that she rarely spends more than $1 "per plate."
Mary and Erin differ greatly on their view of coupons. Erin swears by them, and devotes most of the non-recipe section of the book to them. Mary, however, outright says that she rarely uses them. Her reasons are that most food coupons are for highly processed brand name foods that are either unhealthy or have much cheaper generic counterparts. Honestly, most generic foods taste the same. Instead of focusing on coupons, Mary utilizes foods that are inherently a better value to begin with.
Erin does offer some homemade items, such as basic sauces and salad dressings, but you'll find a much larger section on such items in Mary's book. One other thing you will not find in Erin's book is desserts. I believe desserts have their place at the dinner table on occasion, especially if you have children.
As for the recipes themselves, I tried a few of Erin's, and they were just ok. Most of these recipes you could probably come up with yourself or find online, really. There were some I didn't even have to try because I knew how'd they turn out (I cook a lot), and I have a hard time believing kids will eat a few of these. Ziti pasta with plain white sauce and no spices? No thanks. I've tried several of Mary's recipes, and all but one have been really good.
Long story short...everything in this book that's worthwhile can be found in Mary's.
