We have been working on exactly that at Neeva and the response has been very positive in terms of growth and adoption. Neeva offers a freemium model (free basic and premium for $5/Month which includes paid versions of VPN and a password manager), you can connect third party apps like dropbox and email putting all your personal docs in one search along with websearch, both versions are ad-free and private, it's available to anyone in U.S. and we are building our own independent stack to make the search experience unique and better.