I can provide you with some general information.
Both Home Depot and Lowe's typically offer a range of lumber options, including various types of wood with different dimensions. They may also offer cutting services, which could allow you to get custom dimensions for a piece of wood.
To get a piece of wood with the custom dimensions you mentioned (1 inch thick by 3 feet by 1 foot), you have a few options:
Look for Pre-Cut Pieces: Some stores offer pre-cut pieces of wood in standard dimensions. You might find a piece close to your desired size, but it might not match your exact specifications.
Cut to Custom Size: Some stores may offer cutting services, allowing you to select a larger piece of wood and have it cut down to your desired dimensions in-store. Keep in mind that there could be a fee for this service.
Specialty Lumber Section: In some larger stores, there might be a specialty lumber section where you can find a more extensive selection of wood types and custom sizes.
Regarding the cost, it depends on the type of wood you choose, whether it's hardwood or softwood, and other factors such as the grade and quality of the wood. Generally, larger pieces of wood or specialty cuts may be more expensive than standard dimensions.
To get an accurate cost estimate, I recommend contacting your local Home Depot or Lowe's store directly. They will have up-to-date information on available lumber options and can provide you with a quote based on your specific requirements.