I'm not experienced in licensing or selling copyrights of photos, but rule of thumb I've been told to start with $1000 (USD) for the copyright transfer aka BUY OUT, the best option generally for them (and you sometimes) is to lease aka rent or known as to us photographers License it from you for a much lower cost, dependent on the type of usage, time of usage, and many others things... but I mainly go off of period of time they need it for in 6month packages, and 12month packages. I also offer bulk licensing to encourage them to get more with discounts added in... I also sell my photos and in the process right now of selling my first assignment with a very big commercial client, and selling a package of 5 photos' copyrights to transfer the copyrights to them. For example, I charge a universal one time usage for user under a flat rate, such as if they are going to strictly use it for one run of a print ad, used on posters for internal purposes, I give them one flat rate of that one time use. Another way is the 6month term where they can do more (if you want) magazines, online, etc... or anything/all... your choice but also matters if it is your stock library photos or an assignment you were hired for... I get hired to produce the photo then get paid for the labor of that production, then they can buy/license the photos from me... which can be included with the labor if that is possible with the client, which may or may not.
