Sources say Dropbox paid $100 million for Mailbox
Inside sources are a bit split on the actual total cost to Dropbox. One source told GigaOM that Dropbox paid about $50 million to purchase Orchestra, the company behind Mailbox. But, another source for GigaOM, as well as a source for TechCrunch both quoted the sale price at closer to $100 million in cash and stock.
Also, according to GigaOM, both Yahoo and Facebook had also been interested in purchasing the company, which could have caused a bit of a bidding war, and driven up the price.