Teachers do have summers off, but they do not get paid during the summer. Sounds like most jobs...you work then you are paid.
The numbers posted are inflated because 9.25% is automatically deducted for retirement. 401Ks do not automatically deduct without an employee's approval. The health care numbers are also included for an additional $20K. I highly doubt IUSD pays full price to a healthcare group provider but I guarantee they report the full value. If you want to know a teacher's salary before deductions the they are listed online under the districts salary schedules, then deduct at least ten percent for take home pay before taxes.
Don't think about classroom donations as something for the teacher. Think about providing an additional resource to your student so they can grow. This is a priceless investment. Would you be happy to know most classrooms aren't even given tissues.
As for most people who give teachers a hard time then please sign up to teach. You can start immediately as a substitute with an emergency credential. You will quickly notice that a teacher's day doesn't start when the students start and it doesn't end with the students as most are grading and lesson planning at home.
Choose to invest in the classroom first instead of jumping to a tutor who doesn't work within the classroom. That's how your child will grow in the long run.