You can purchase a resistor from various sources. Here are a few options:

1. Local Electronics Stores: Visit your nearest electronics store, which often carries a wide range of components, including resistors. Look for stores that specialize in electrical or electronic equipment.

2. Online Retailers: Explore online platforms such as Amazon, eBay, or electronics-specific websites like Digi-Key or Mouser. These websites offer a vast selection of resistors with different specifications and sizes.

3. Hardware Stores: Some hardware stores may have a small section dedicated to electrical components, including resistors. However, the availability and variety of resistors may be limited compared to electronics stores.

4. Salvage Electronics: If you're looking for a specific resistor that may be difficult to find or expensive, consider salvaging it from old or discarded electronic devices. However, keep in mind that this option requires some technical expertise to correctly identify and remove the resistor.

When purchasing a resistor, consider factors such as the resistance value, wattage rating, tolerance, and physical size. These specifications depend on the specific application and circuit requirements for which you need the resistor.