Blog that teaches how to connect Unity's HLAPI with Steamwork's matchmaking in order to avoid networking fees. http://www.unitystudygroup.com/unetsteam
Interested in networking? Unity offers a high level API networking solution called UNet, which is quite appealing for many developers. However.. Matchmaking aint free, and using their services can get expensive. Same strikes true for other third party networking frameworks such as Photon, leaving developers thinking "if only there was a way to use Unity's networking features without having to rely on expensive matchmaking services!"
Well if you are one of the many developers that plan on releasing their games via Steam, then you're in luck. Steamworks offers matchmaking as a free service. You can use the Steamworks SDK to obtain client/connection info, then serve it to the UNet API and voila, you can use everything that Unity has to offer, for free! This is a guide for connecting Steamworks matchmaking services to Unity's hlapi, at the time of writing this there are virtually no resources on the subject so I hope this blog post serves as helpful tool for getting started.
Read the rest of the blog at http://www.unitystudygroup.com/unetsteam