In the good old days, lesson plans were a list of various subjects with snack, lunch, specialists, and other scheduled times. Then teachers would run off copies of subjects that were already covered. It was frowned upon to instruct new materials. All Substitute plans were supposed to have been subjects that had already been covered. This way, all students should know what to do, as this was a review day. Over time this structure would change somewhat.
At the beginning of the year, teachers are given a copy of all their scheduled times for the year. The Math, Reading, lunch, and Specialist block. Using those times as a template, we attempt to fit in all of the remaining times with the required amount of minutes. A copy of this is sent to the office. As much as possible, subjects are planned at the same time each day. The template is enlarged and placed within a binder. The pages are numbered and dated. It is very difficult to make lesson plans a week in advance. Let me clarify that. It is difficult to follow plans that are made a week in advance. What happens if a subject runs over? What will you do if a math concept needs two or maybe three days? If you have only planned for one day, your timing will be off. Many teachers write the lessons for the day they are working on, which is not difficult if you are following a format. Or, teachers write a week in advance and work as close to the original plan as possible.
Say a school starts at 9:00 AM. The teachers who are at the front door, meeting the custodian at 7:00 AM, are the ones who are very sick and want to spend time making plans for that day. Many teachers go to work sick, as the time to write the plans isn't worth it. Also, Substitutes do not correct any papers. The fabulous ones do, but the majority leave it for you to do. Add another hour to your work day the next day.
I know I spoke about you not buying anything for your classroom. There can be exceptions. There is a book called Mad Minutes which you can get on Half.com. You can run off copies and keep the book. Make 5 envelope folders. Put the day of the week on each one. Put a copy of your weekly schedule in each folder. As best you can, try to align the subjects with already printed activities. I like math quizzes, analogies, Science Fun, and other cool papers. As papers are used, put a copy in another folder to be used again the next year. If you are fortunate enough to work with cooperative teachers, you may be able to get copies that are clever and can be reused. As lessons are used, be sure to replenish them on the same subject. May all your days be awesome.