EsmeraldaX,
You live in Boston, where everything is expensive! So although the price seems a bit high, it does not seem unreasonable to me for Boston-- if you can afford it and are happy with the kennel. you should probably just stick with the one you've found.
There might be another option, however: some pet sitters will take the pet to their own home and keep the pet there. As I am sure you already know, Tufts University's vet school is in Grafton. The tuition at this school is very high and the veterinary students graduate with a large amount of indebtedness. There might be a number of eager veterinary students who might pet sit in their own homes for a bit less. Finding someone might be hard-- you could contact the College and find out what the procedures are for getting the word out (an e-mail would be best, but they might only let you put up a flyer).
I am a professor at a College of Vet Med-- I have the world's greatest pet sitter (a vet student of course) who comes to the house three times a day for only $10-- this is a crazy-low price for 2 cats and a dog and we always pay her more than she asks for. The only problem is that she will graduate in 18 months!
Beatnik