I read with concern a report this morning that stated that Google was going to start charging for placement on Google search. The report, that appeared in a national newspaper, seems to have been misleading.
Google does have certain paid advertising that you can buy to receive highlighted placement at the top of the search page, but if SEO is done your business can more than likely appear near this prime real estate for free. So it's up to you if you want to pay extra for that top space. Personally, when I search for a product, I don't usually go with the top spot just because it's the top spot.
Google also has Google Product Search, a place where you need to go in separately and list your product. This is a free component and gets your product listed in the search results when a potential customer clicks on shopping on their Google search page.
And then there is the paid advertising that helps with adwords in local Google searches. This is for a fee, although most of the time you can try it for free. I've been told by a manufacturer with a limited and unique market that this is worth the money. Again, you are paying for the top spot, not to be the only listing.
To pay or not, is a decision that depends on your product, your competition, and how your business appears on the search engine after doing diligence with SEO. If you have a local market where your competition is stiff, it may be worth the expense to be on top.
But keep in mind, you will only be affecting those potential customers who do Google searches not those who use other search engines like Bing.