If you travel alone and are tired of paying high single supplements, consider the offerings of On the Go Tours (www.onthegotours.com) of Britain. The company specializes in tours to exotic destinations, and its voyages offer the possiblity of avoiding an extra charge for travelling alone if you are willing to share a room with another person of the same gender.
Their tours cover a lot of territory--Asia and Central Asia, Russia, Africa, etc. They have tours on the TransSiberian train that permit some stopovers at fairly reasonable prices. On the Go Tours was named the best medium tours operator in Britain in 2012. I'm not sure what this means, but presume medium refers to price, not quality.
Some people are relucatnt to share rooms with strangers. I have done it several times, once on a safari where I shared a room with a pleasant British girl, several times on Atlantic crossings where I shared with older women, and once at a Club Med in the Caribbean. I never had a bad experience, and found it a useful way to save money while travelling.