I teach at a middle school (5-8) in CT and our district is by no means well off. Even though, I've my average art budget per year (for approx. 400 students) is over $6500. Our high school teacher has a budget of over $8000! I have been teaching for over 30 years and have managed to increase that amount every year. I think one of the reasons is that my administrators see the wonderful things I do each year with my students and how Art (and music) classes improve learning in so many ways.
I concur with all the previous advice that others have given to you. I would also recommend making sure to contact the PTO to see if they have extra funds. Going in to see your principal re. what other teachers in other districts and situations that are similar will help to open his/her eyes as to what you need.
Be a strong proponent for your program. Put up didactic displays of your student's work and make sure to keep them fresh and rotated often. Contact supportive and vocal parents to speak to your local school board. School boards listen to parents! Remember...your program is all about servicing the children in your school so as to make them appreciate art and gain an understanding of how art affects their lives on a daily basis.
Put up student work in the Board of Ed offices, town hall, local banks and your library. Institute an "Artist of the Month" program in your school. Initiate a "Family Arts Nite" This will get parents involved and into the school to actually participate in Art with their children. I've done this before and it is met with incredible success!
You can check out the following program and participate in it. It is called the "Empty Bowls" project- a program to help the hungry (http://www.emptybowls.net/). Very fulfilling for both families and those that benefit from it.
Do some research into what the district spends on other student activities such as band, chorus, sports, field trips, etc. That could be offer some leverage in increasing your budget.
Consider taking some field trips to local art museums. Talk to the PTO about assisting with funding.
Team up with other faculty and do cross-curricular projects to get your program and your teaching skills noticed by the administrators, parents, board and students.
Come up with some interesting projects that could beautify your school such as permanent installations. Over the years I've done 15' totem poles (carved out of red pine), painted murals, mosaic murals (yes we even made our own tiles), batik banners, and even 7 huge stained glass windows in the cafeteria!
Your clay issues may mean that you need to reconstitute your clay. Let it dry and then pound it to small pieces with a sledge hammer. Make sure to do this outside and wear a dust mask. Put the pieces into 5 gallon pails and let it sit for a week or two. Pour off the excess water and you have slip. Pour the slip onto plaster drying bats. You can make some wooden frames say 2'x2' and line them with a plastic garbage bag. When the plaster is really dry, then pour the slip onto the bats to harden. When it is the correct plasticity, then wedge it and bag it. You may be surprised how it turns out.
I would also recommend finding and applying to a number of art grants. Although this may help in the short term, though, it is not a long term solution to your issues.
Be proactive, work hard making your needs known, and good luck. If you build it, they will come!
This e-mail is intended solely for the use of the individual to whom it is addressed and may contain information that is privileged, confidential or otherwise exempt from disclosure. If the reader of this e-mail is not the intended recipient or the employee or agent responsible for delivering the message to the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please immediately notify us by replying to the original message at the listed email address. Thank You.