The VALUE of a tutor (note- this is different from the price of a tutor) is based on a tutor's ability to not only know the subject content/matter, it requires some one who understands how children learn and have multiple ways to explain a concept. The largest differentiator when you compare tutors is finding some one who also understands the proper way (no shortcuts) to teach math and science, how reading and writing (language skills) develop in a simultaneous manner and can converse in the area of why it is not good to teach misconceptions.
After working for years in education and having been around top notch and new teachers, I have seen and experienced how easy it is for some one to 'teach' anything. One example of this is FOSS science, designed originally for elementary school teachers who lacked an actual science background. It was created where the instruction could be followed by a sub so even if the teacher was out, science need not 'suffer'. New math was supposed to be better than regular math. New math managed to not teach my generation how to learn and use math so I went back to college to do this task. Writing a five paragraph essay is a minimum threshold to barely scrape by on a satisfactory/passing scale. It is not a level to stop at nor to imagine as success.
When a parent is searching for a tutor, they should be looking for some one to do much more than help a child complete a homework assignment. Homework is something which is mini-version of a content task related to something the student learned in school this particular day or in the past and is need of review. A tutor is some one who assists a student in developing and polishing a new skill, making sense of the concept in the bigger scheme of things and pushes a student forward towards wishing to know more, practice more, learn more. In addition, a tutor is able to help a student figure out ways to study (which is what great students do above and beyond the homework) so the learning process is ongoing.
A tutor should be able to read and interpret an agenda book, what the teacher comments on the paper, report card, etc. mean (no matter how PC and well intentioned) and work with the parents and students and possibly the teacher in helping move the student forward at the respectable rate of the class OR a bit further.
Checking and reviewing homework is fairly easy as it is review - moving forward with gaps filled in and enthusiasm to learn is a whole other story. The price differential is often based on the tutor's ability to identify the rut/problem the student is having, correct it and make the concept understandable and adding joy.
Make sure you know what your child needs in a tutor as you decide what you are willing to pay. Not having cable for a few months may well be the better investment in your child's future as opposed to just getting them 'through' the current hurdle.