This is what you can buy when using services you don’t pay for.

A Russian billionaire investor paid $100 million for a French chateau-style mansion in Silicon Valley, marking the highest known price paid for a single-family home in the U.S.

The purchase of the 25,500-square-foot home in Los Altos Hills, Calif., underscores the strength of some luxury properties in an otherwise depressed housing market.

The buyer, Yuri Milner, 49, who heads Digital Sky Technologies and whose investments include Facebook Inc., Groupon Inc. and Zynga Inc., had no immediate plans to move into the home, said a spokesman.

Mr. Milner is the stocky founder of DST, a Moscow-based fund that’s made a splash in Silicon Valley via its investments. Its first in the U.S. was a $200 million check for Facebook in 2009. His primary residence is in Moscow, where he lives with his wife and two children.