For example Coca-Cola's logo was designed by Frank Mason Robinson in 1885 for $0. Mr. Robinson was John Pemberton's bookeeper. Google's logo was developed for $0 as well. Sergey Brin, one of Googles founders in Gimp, designed the logo in 1998. Since then it has been tweaked but not modified.
The original BP ( British Petrol ) logo was designed for $211,000,000. In 2008 the logo was updated.
My favorite logo design of this bunch is the Enron logo designed by Paul Rand in the 1990's. Too bad this great design is associated with a company like Enron, but I must say the founders were definitely not slackers when it came to design or hiring a designer to make them look good. The price tag? $33,000.