Which one is the positive side?
The 2N2222 base voltage should never exceed about 0.7 volts while the collector voltage could go as high as the supply voltage. In most cases if using a polarized capacitor the positive lead would go to the collector. 3.3uf is fairly large for a ceramic typical max 1 to 2uf, film capacitor go up to 100uf and are non-polarized. Polarized Tantalum up to 470uf and Aluminum Electrolytic Capacitor(Very Large). What you used depended on how stable the frequency requirement. Temperature affects many types of capacitors, electrolytic are usually the least temperature stable device.