Blu ray copying and burning is still a rather expensive hobby at the moment. Most of the burners are still in the $200 range, like this one that I have: http://www.newegg.com/Product/Product.aspx?Item=N82E16827136155
In order to backup commercially made Blu Ray movies, you'll need a software program to break encryption on them, and at the moment the only one available is AnyDVD HD. http://www.slysoft.com/en/
The price on it varies depending on how long a license you choose, but it looks like they are still offering the program with lifetime updates for â‚¬109.
Blu ray media is also rather spendy, with common prices in the $6.50 range for 25gb BD-R disks, and twice that for the rewriteable BD-RE 25gb disks. 50gb disks are also available, though much more costly.
Many blu ray movies are larger than 25gb, so you might have to take out extras, or unnecessary language tracks...to do this look into a free program called tsMuxer. And there is a compression program in the works, though still in beta form, called BD Rebuilder. Look through some of the threads in this forum regarding it, or look at the DVD Rebuilder forum over at doom9 forums.
Some of us have been compressing and going to 25gb Blu ray disks, or double layer dvds using BD Rebuilder. Be aware you need a fast computer, quite a lot of storage space and a lot of time to encode HD video. Expect 10 to 16 hr encoding times, depending on the speed of your computer. Dual core cpu is a must...quad core would be better.
Blu ray disks are larger, and they do take more time to rip and burn. I would advise using ImgBurn in UDF 2.5 mode to burn to blu ray disks.