Here are a few places you can buy canvas:

1. Arts and Crafts Stores: Many arts and crafts stores carry various types of canvas for uses such as painting, crafts, and decorating. You can go to your local art supply store or craft store and find a canvas that suits your needs.
2. Online Stores: Many online stores offer a wide variety of types and sizes of canvas. You can search and buy canvas on large e-commerce platforms (such as Amazon, JD.com, Taobao, etc.) or professional art supply online stores.
3. Wholesale market: Some cities will have a dedicated wholesale market or stationery wholesale market, providing canvas of various specifications and qualities. You can go to these markets and contact suppliers or wholesalers directly to buy canvas.
4. Manufacturer or supplier: If you need a large amount of canvas or have special requirements, you can directly contact the manufacturer or supplier of canvas to learn about their products and prices, and make bulk purchases.

When shopping for canvas, you can consider the following factors:

• Canvas Type: Different types of canvas are suitable for different purposes, such as oil painting canvas, watercolor paper, drawing canvas, etc. Choose the right canvas type according to your needs.
• Size and specification: Choose the appropriate canvas size and specification according to your project or creative needs.
• Quality: The quality of the canvas will affect its durability and painting effect. Choosing a canvas with good quality can get a better user experience and work effect.

Please compare different purchase channels according to your needs and budget, and choose the right canvas supplier or merchant.