What is the value of 5000 dollars in 1950?

It would be worth 500 dollars because the amount of money never changes over time. The purchasing power of a US dollar now is about 10-12% of its purchasing power in 1956. The easy way to determine this is with an inflation calculator that is based on changes in the CPI. I recommend http://data.bls.gov/cgi-bin/cpicalc.pl