I got a cheap shamisen for $230 dollars and while tuning the san no ito made of a thin wire, it snapped! And while playing on the remaining strings the ni no ito, you guessed it, snapped. If you look up shamisen on amazon you’ll see one by glmusicstore. As I said the san no ito was made by a thin wire and the ni no ito by a plastic woven plastic string. 
getting new strings
Yeah you need to get some real strings. Metal strings have no place on the shamisen!
That is so wired! I mean weird! I (playing a SanXian) use cheap monofilament fishing line in different weights - works great, plenty loud, and no worries about if I break a string, which almost never happens. The twisted silk cord I still have reels of, however…