A patent search with a patentability opinion, which will determine if the patentability requirement can be satisfied can range from 500$ to 3000$, depending on the cost of search and level of analysis that you want. The search for a freedom to operate opinion would alone cost atleast 3000$, and would return dozens of references that a patent attorney must wade through in painstaking detail. Typically a freedom to operate opinion will cost at least $10,000, and sometimes substantially more. It is not at all uncommon for a freedom to operate opinion to cost $20,000 or $30,000, or more.

What is Patent Search?

The purpose of patent search is to determine, the purpose of a patent search is to determine whether it makes sense to move forward with the expense of preparing and filing a patent application. There are well over 7.6 million US patents that have been issued and well over 1 million pending US patent applications. Searching through these number of patents takes time and skill, and a US patent search can and does quite effectively sift through these patents, assuming of course you have a professional do the search. Notwithstanding, there are many millions of other references and foreign patents and applications that can be used by a patent examiner to reject claims.
With all patent searches, regardless of who does the search, there can be no guarantee that all relevant prior art will be found. Specifically, pending US applications are not published until 18 months after they are filed, so even with an exhaustive, comprehensive patent search that left no stone unturned there is no way to be sure that everything pending at the Patent Office has been discovered.
The key to obtaining a patent is to have an application with sufficient disclosure so that if an examiner does make a rejection you can amend your application as necessary and obtain a patent. Therefore, it is important to understand that the goal of a patent search is not to guarantee that there is no relevant prior art that will bar patentability, but rather to investigate whether proceeding with the expense of a patent application makes sense given the rights that can likely be gained.

What is a Freedom to Operate Opinion?

It is understandable that those who are entering into a business endeavor would want to know what their potential exposure might be, and when you have an invention perhaps the single largest potential liability looming is the threat of infringing a patent owned by another. This being the case, it is understandable that individuals and small businesses would like to be able to obtain a patent search and opinion that if they were to do what they are about to do they would not be sued for patent infringement. The analysis required in order to make this determination is daunting, takes a lot of time and comes with substantial liability for the patent attorney who offers the opinion.

What this adds up to is fa freedom to operate opinion costing a lot of money. Allow me to explain why?

First, a patent search is only the first hurdle with respect to opining whether someone is likely to be sued for patent infringement. In fact, the patent search needs to be a clearance search, and the searchers know that they are going to be held accountable if they make a mistake, so they are only willing to provide a clearance search for an amount the reflects a substantial premium compared to what they charge for a patent search. This only makes sense. If they make a mistake and miss something and you spend $10,000 to file a patent application they have limited exposure, and that is if you even decide to go after them. If they offer a clearance search and make a mistake their exposure would easily be hundreds of thousands of dollars, perhaps millions of dollars.
Second, the act of filing for and ultimately obtaining a patent is not an act of infringement. You can, in fact, obtain a patent for a device that if made would infringe the patent of another. The question with respect to patentability is whether the invention is useful (easy to satisfy), novel (i.e., exactly identical to something in the prior art) and nonobvious (i.e., an invention is obvious if it is a trivial or common sense re-arrangement of the prior art).

With respect to infringement, the question is whether all of the elements of the claim in question are present in the allegedly infringing device. So all of the elements can be present, but the device such an improvement that the improved device is useful, new and nonobvious. Indeed, there are many reasons to obtain a patent on a device that might infringe a patent, including creating leverage for a licensing deal and/or the ability to make the improved device without competition from the original patent owner after the underlying patent has expired.
Third, most times when an inventor wants a patent search they come with sketches, drawings or an explanation of the invention. Sometimes a prototype will be available. In order to provide a freedom to operate opinion the device as it will be made must be defined with concrete certainty. Opinions are not provided in a vacuum, they are provided with respect to a specific context. A freedom to operate opinion can opine that if you were to do X differently or Y in a certain way it would be better, but there needs to be context. Typically when we do patent searches and offer opinions a big part of what we do is to identify space for the inventor to move into where a patent could be obtained. This is early stage investigation, and with an eye toward whether a patent can be obtained, not late stage analysis of whether a legitimate claim for infringement can be made.
Fourth, it is impossible to determine whether an device would infringe without obtaining the complete file history of each patent that is close. You simply cannot tell from reading a patent whether a device will infringe. This is because everything in the file history, all the arguments made to the examiner and papers filed work to either narrow or expand the definition and meaning of terms in the patent application. You simply cannot assume the meaning of words or what the examiner understood or appreciated, you need to read and consider the entire file. This means you have to obtain the file and then pour over it with extreme detail, and in many cases to provide a freedom to operate there will be multiple patent files that need to be considered. This takes time.