user52962: My client asked me to use the bitcoin blockchain to store some photos hash as proof of existance.
I read that pulling this data on into the blockchain is not free
1) How much does it cost ?
2) Who gets that money ?

user54370: I guess not many would like to reply you to that question as storing data into any digital currency blockchain is bad approach. Most would take it as a question how to spam which mostly was not very well accepted in cryptocommunity.
However, I think this platform is about questions and answers. 
There are several methods, those 2 are best covered:

OP return code
P2SH

OP return code method costs much more. You can read here more about it or even test it.
Many fall currently for the hype to store data in bitcoin or some other popular projects, this is mainly driven by not understanding at all what for and why should I do not do that, keep that in mind please

user26940: I suggest you look at opentimestamps. From the website:

A timestamp proves that some data existed prior to some point in time. OpenTimestamps defines a set of operations for creating provable timestamps and later independently verifying them. At the time of writing timestamping on the Bitcoin blockchain is supported, the format is flexible enough to support a variety of methods.
Anyone could realize a timestamp with the permissionless blockchain by paying the transaction fees, for your convenience we offer calendar servers that perform this operation for you. These servers are free to use and they don't require any registration or api key.


52962: <p>My client asked me to use the bitcoin blockchain to store some photos hash as proof of existance.</p>

<p>I read that pulling this data on into the blockchain is not free</p>

<p>1) How much does it cost ?</p>

<p>2) Who gets that money ?</p>
 54370: <p>I guess not many would like to reply you to that question as storing data into any digital currency blockchain is bad approach. Most would take it as a question how to spam which mostly was not very well accepted in cryptocommunity.</p>

<p>However, I think this platform is about questions and answers. </p>

<p>There are several methods, those 2 are best covered:</p>

<ul>
<li><a href="https://en.bitcoin.it/wiki/OP_RETURN" rel="nofollow noreferrer">OP return code</a></li>
<li>P2SH</li>
</ul>

<p>OP return code method costs much more. You can read <a href="https://21.co/learn/embedding-data-blockchain-op-return/" rel="nofollow noreferrer">here</a> more about it or even test it.</p>

<p><strong>Many fall currently for the hype to store data in bitcoin or some other popular projects, this is mainly driven by not understanding at all what for and why should I do not do that, keep that in mind please</strong></p>
 26940: <p>I suggest you look at <a href="https://opentimestamps.org/" rel="nofollow noreferrer">opentimestamps</a>. From the website:</p>
<blockquote>
<p>A timestamp proves that some data existed prior to some point in time. OpenTimestamps defines a set of operations for creating provable timestamps and later independently verifying them. At the time of writing timestamping on the Bitcoin blockchain is supported, the format is flexible enough to support a variety of methods.</p>
<p>Anyone could realize a timestamp with the permissionless blockchain by paying the transaction fees, for your convenience we offer calendar servers that perform this operation for you. These servers are free to use and they don't require any registration or api key.</p>
</blockquote>
