In the UK, I did a search for a gallon size glass jar. The first several pages of results was Amazon, Etsy, eBay, HobbyCraft etc... All useless sites. So after looking about, I found out you can ask Google to stop certain sites coming up in a search. So for example - Gallon glass jar -site:amazon.co.uk To block multiple sites - Gallon glass jar -site:amazon.co.uk -site:ebay.co.uk -site:hobbycraft.co.uk Just repeat/tag on as many sites you want.
You can use the same syntax to limit your search to a single site: "Bollocks" "Nonnie" site: www.politicalforum.com