Toner cartridges are essential supplies for laser printers, copiers, and fax machines. They contain toner powder, which is used to produce printed text and images on paper. There are many places where you can buy toner cartridges, both online and in-store. Here are some of the best options:

1. Office supply stores: Office supply stores like Staples, Office Depot, and OfficeMax are great places to buy toner cartridges. They offer a wide range of brands and models, both genuine and compatible, and often have sales or discounts. You can also speak with their staff for expert advice on choosing the right cartridge for your printer.
2. Electronics stores: Electronics stores like Best Buy and Fry's Electronics carry toner cartridges for a wide range of printer brands and models. They often have competitive prices and may offer promotions or discounts on certain products. They also have knowledgeable staff who can assist you with your purchase.
3. Online retailers: There are many online retailers that sell toner cartridges, including Amazon, eBay, and Newegg. Online retailers usually offer a wider selection of products than brick-and-mortar stores, and many of them have user reviews and ratings to help you make an informed decision. You can also compare prices from different retailers to find the best deal.
4. Manufacturer's website: If you prefer to buy genuine toner cartridges, you can visit the manufacturer's website to purchase them directly. Brands like HP, Brother, and Canon have online stores where you can buy their products. You may also find discounts or promotions when buying directly from the manufacturer.
5. Refill services: If you want to save money and reduce waste, you can consider using a toner cartridge refill service. These services refill your empty toner cartridge with new toner powder, saving you the cost of buying a new cartridge. You can find refill services at office supply stores, electronics stores, and specialty shops.

When buying toner cartridges, it's important to consider the type and model of your printer to ensure that the cartridge you buy is compatible. You should also compare prices and read reviews to find the best product for your needs. If you're buying a compatible or remanufactured cartridge, make sure it comes with a warranty to protect against defects or damage.

In conclusion, there are many places to buy toner cartridges, including office supply stores, electronics stores, online retailers, manufacturer's websites, and refill services. Each option has its advantages and disadvantages, so you should choose the one that best fits your needs and budget. When buying toner cartridges, make sure to consider compatibility, price, and quality to ensure that you get the best value for your money.