I agree with you on the Ecce Romani, it is a wonderful book. My high schooler is currently on his 3rd year of Latin, and he used Ecce in 7th grade, in private school, and is now using it again in 9th grade, in public school. It seems like a much more interesting way to teach Latin than just memorizing a list of vocabulary words. I'm trying to locate a used copy of the first book at my local home school store but so far I've not been able to find it.
I will keep looking for cheaper alternatives.
Some Latin study sites for ya!
http://artemis.austincollege.edu/acad/cml/rcape/latin/01index.html
http://www.textkit.com