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If it's a small mom and pop manufacturer, then they will be spending to get the word out about their products.
Manufacturers are marketing to distributors and wholesalers (usually). B2B as it were. They can and do spend a lot in various trade journals, trade shows, etc.
Dealers are marketing to retail (still B2B) or end consumers.
You need to consider the who and compare it to your traffic base before you go looking to sell advertising.