Of course, you can collect anything that you like. If you are wondering if R.S. Prussia items are of some value, the answer is yes. R.S. initials stand for Reinhold Schlegelmich. The name Schlegelmich shows up on several factories in the city of Suhl in what was once Prussia and is now Germany. They made fine porcelain from 1869 - 1956.
R.S. Prussia has been reproduced as well as a fake. You can learn about fakes and the background of RS Prussia on Ruby Lane's Real or Repro page featuring that company.
One indication of an authentic, high-quality piece is if it is translucent. That means that a piece, when held up to a light, will show a silhouette of your finger if you hold your finger up behind the lighted item.
Learn more by checking out the International Association of R. S. Prussia Collectors online. You can also check prices online.