If you want to be a completist but prefer to pay for your ripped copy, you can buy the Hong Kong VCD version of Serenity for a lot cheaper than the DVD. This is the complete movie in English, with Chinese subtitles.
The quality of VCDs cary wildly but generally they’re about the level of a good video copy. Most VCD movies are on 2 discs (as this is) because you can only get about 70 minutes of video on a CD. Many DVD players will play it, as will your computer and some handheld players.
However, I have no idea if Universal or our BDHs see any revenue from this. Just sayin’.