I still like the original Doom Shareware model. They gave you what felt like 1 whole game for free, enough that really impressed you and gave sense of a complete product.
Then they made an offer of 2 more games (or episodes) for a fee. When taken as a whole, they were only giving 1/3 of the game away for free, but before purchasing, you felt like you were given an entire unit upfront.
This established a great relationship between the user and ID software. They demonstrated for free what 1 unit of Doom was, then offered 2 more -- which I roughly understood what value I would get.
I think creating and segmenting units of a product that are complete in themselves, but related to other premium offerings is a great way to get a user to feel both satisfied with a free product but yearning for more. It also shows that segmenting your sales narrative in freemium is very important. I get irritated when you interrupt my free unit and offer the rest at cost. I am happy when I receive a whole unit for free, then am offered more units for a fee.
League of legends is having massive success with a similar model too. You can do and experience just about every aspect of the game for free without annoyances or interruptions about paying and many players start playing for just that reason then invest a great deal of cash into the game a few months or even years down the track when they're hooked.
To expand on this: virtually everything is paid for by in game currency you can earn by playing games. Every game you play makes you money (you earn more for longer games). Using that money, you can buy almost everything.
The equipment you can buy with the in game currency gives you a real advantage in player vs player battles. Having no equipment at all means you need a very large skill advantage over the other players to be able to win games.
To get all things you might reasonably want to buy, you need to play an uncomfortable amount of games - which gets many people to take a shortcut and buy the in game currency with real money instead of obtaining it by playing games.
Then they made an offer of 2 more games (or episodes) for a fee. When taken as a whole, they were only giving 1/3 of the game away for free, but before purchasing, you felt like you were given an entire unit upfront.
This established a great relationship between the user and ID software. They demonstrated for free what 1 unit of Doom was, then offered 2 more -- which I roughly understood what value I would get.
I think creating and segmenting units of a product that are complete in themselves, but related to other premium offerings is a great way to get a user to feel both satisfied with a free product but yearning for more. It also shows that segmenting your sales narrative in freemium is very important. I get irritated when you interrupt my free unit and offer the rest at cost. I am happy when I receive a whole unit for free, then am offered more units for a fee.