I start this description with a strong recommendation: purchase only small quantities of chemicals and reagents. When I visited the Holy Cross Regional School chemistry lab during 2011, I observed a cabinet full of large bottles that were at least several years old. The one bottle that made a lasting impression was uranyl nitrate.
For this enrichment chemistry laboratory, keep in mind that your primary measurement instrument is a Vernier spectrophotometer, which measures solution concentrations of molecules that absorb in the visible wavelengths. This means molecules such as food colors and ions such transition-metal salts.
Transition-metal salts are particularly useful to teach students to develop skills in using pipettes and volumetric flasks to create solutions of known concentrations. Potassium dichromate and potassium permanganate are strong absorbers of visible light; their solutions must be extremely dilute.
For the 10th-grade lab at Holy Cross Regional School, Lynchburg VA, the highest priority is for safe chemicals. It is surprising that a supermarket is an excellent source of common solvents that are both safe and inexpensive. Examples are distilled water, isopropyl alcohol, and distilled vinegar. I did not purchase vitamins and minerals because I did not know what to do with them. Food colors, both normal and NEON come in packages with four different colors.
The only chemicals that are required, outside of a supermarket, are transition metal nitrates and chlorides, porous solids, activated carbon, silica gel, acetone, and strong acids and bases.
I believe that I have credentials to make the above recommendations. Between 1964 and 1975, as a research chemical engineer I performed thousands of chemical kinetic runs using a polarimeter (Monsanto company) and an expensive, Varian UV-visible spectrophotometer (Monsanto and Virginia Tech).