If you just want to enjoy a fun, Big Bang Theory item, then by all means purchase these!  The Amazon price is decent, while other online shopping places are rather expensive (well over $20).  However, if you are looking for a quality item, then this is not it.  The fabric is very, very thin.  It is definitely not designed to keep the wearer warm, nor to hold up to any type of strenuous activity.  But they are fun!