I think I spend less as a vegetarian. I can't be sure since I was a little kid when I stopped eating meat, but I stock up on things like pasta, beans, cereal, and rice about once a month. All I buy most weeks is fresh fruit and vegetables.
As far as cruelty, Jonathan Safran Foer said that from what he saw, egg laying hens are treated the worst by far and that if you give up any one thing for ethical reasons alone, it should probably be eggs. It also seems that dairy cows are treated just as bad, sometimes worse, than cows used for meat (based on what I've read, not personal experiences or anything.)
Also, LisaR, I really liked Dr. Esselstyn's book, and I've been looking into Dr. McDougall's programs. I basically followed them already, since I have nut and soy allergies, but I used to eat some olive oil. I cut out the oil like a month ago. I know they say not to worry about fat, but I can't imagine I'm getting enough. I calculated it the other day, and I only had like 16g that day? Is that way too low? I can only find their recommendations on percentage of fat, but not in grams.