On SE sites such as Super User, they are off-topic because they tend to become obsolete quickly. However, since this is not technology, that concern isn't so great. Product recommendations will always be attracting of spam, however.
I propose that a close reason that essentially states "no product recommendation requests (outside of common household items)" be added.
I don't think so. Not so far as specific models/brands/etc unless it relates very specifically to the task at hand where other brands/models don't (i.e. you discover one brand of alcohol that can make you fly, then recommending that brand for people asking how to arrive places on time would fit).
I think products that solve a problem being asked about is fine, but recommending one particular one over another rather than suggesting people find a form of that product with trait X which is the key to solving the hack (only use alcohol brands that can make you fly to enhance your punctuality).
The use of product recommendations by way of example shouldn't be off topic though. Simply linking to a product without further explanation or ideas should be.
Product recommendations are ok. I don't think spam will be much of a problem, simply because it seems that the products recommended will tend to be rather generic like recommending Ajax for something as an example. You will know spam when you see it, just flag it.
