A guideline that I have found useful is to always have 3 months operating cost in the bank and enough money to carry our expenses until the first fundraiser in the fall. For example our first dance, open house and training opportunities happen before our November fundraiser. We carry over enough to cover ourselves and it is stated in our standing rules.
Our 2 PTO's separate Bylaws stipluate that we carry over a minimum of $1000 (K-1 school)and $2000 (Gr 2-5 school). We are trying to get as close to that figure as possible, esp at the primary school since the kids are there for such a short time that they should enjoy the benefits of the fundraising, and not carryover tons of extra money.
As far as carrying over money for a specific purpose: we would need to vote on that since it is, basically, a revision to our already-approved budget.
The first question I would like to ask you is what does the principal have to do with the control of the money? Unless he is on the board, but you still need a majority board vote to do that. If the board does't vote that way he cant do anything about it.
As a PTO you are independent of the school the principal can not tell you what to do with you money.
We have in the by-laws a sum of $500 that has to be left for the board next year. Even our bank will not let us depleat our account to nothing. Stay your course and stand your ground!
Our by-laws actually state that a minimun of $2000.00 must be left for the incoming officers to start with. This is because we have had outgoing officers that had the idea to leave the new comers with nothing to work with. One year they had less then $200.00. Talk about a tough road to hoe. But with the bylaw into effect it deals with it.
We have, in the past, voted on a sum of money to be set aside for for a project such as a playground. This dollar amount is moved on the books from the general fund to a line item. As far as the normal budget, if the money is not spent it goes into the general fund to be used for next years budget. This is not listed in the by-laws, but it is not listed that it can not be done.
We also have a line item that states that we keep a couple thousand in the bank for start up. This we voted on but did not add to our by-laws