UNIVAC
In June of 1951 UNIVAC (Universal Automatic Computer) was presented to the U.S. Census Bureau, afterwards Remington Rand sold 46 of the machines for more than $8.3 million each, making UNIVAC the first mass produced computer ever as all of its predecessors were one of a kind machines. UNIVAC was the first computer to use highspeed tape unit for magnetic media, that is still used in our computers today.
IBM
IBM's first mainframe computer the IBM 701 was released to the public in 1952. In 1954 IBM released a smaller version of the 701 called the 650 it was both smaller and more affordable, costing only $500 000 but could also be leased for $30 000 a month. In 1955 a new type of programming called microprogramming was invented by Maurice Wilkes which allowed the base instruction set to be defined or extended by built in programs (now called firmware or microcode) which became widely used in computers. By 1956 IBM was ready to release its first magnetic disk system, RAMAC (Random Access Method of Accounting and Control) the cost to purchase this new system was immense at a whopping $80 000 per mb the average cost per megabyte nowadays is less than 2 cents.