I bought some BD-RE discs a few years ago. That was about when I bought 6 LG BD writers at once. BD-RE writing took forever while I always had multiple SSD drives as well. I also often had more than 10GB of nearly unused RAM space that I could use as RAM disk/drive. Since those BD-RE discs were made by Mitsubishi and Matsushita in Japan, I was hesitant to spend much time with those discs.
Things look a bit different now. Kakaku.com displays several BD-RE 2x products at not-so-high cost. That's is Taiyo Yuden's own retail brand name marketed by Taiyo Yuden group's Start Lab, Inc. in Japan founded long ago by Sony and Taiyo Yuden jointly. Start Lab distributes Taiyo Yuden's optical storage media in Japan and export to a few countries. Some of TY's That's-branded products are not necessarily made in Japan. Made-in-Japan That's media have "Made In Japan" (in Chinese) clearly written on the spindle/jewel case. Those not labelled as such are probably produced in overseas facilities that are probably not soley owned and controlled by Taiyo Yuden. But Made-in-Japan That's DVD-R, DVD+R, BD-R, BD-RE, etc. are cheap enough considering the superior and even quality and reliability.
Here's BD-RE 2x for US$2.4 and they look like 50GB ones from what I see. So that makes US$24 for 500GB, US$48 for 1TB, which is about as expensive as 2.5-inch HDD.
The person from whom I bought the BD-RE discs bought them in Japan. Price then was more like US$20.