No you don't have to pay in order to play second life. There are a lot of places and things that you can do without spending any of the in game currency (lindens) and still enjoy the game.
Chat with our AI personalities
You can give birth in the game "Second Life", which you can download for free. You can also give birth in the game "Sims", which you have to pay for. For a more realistic birth, I would go with Second Life.
Basic membership of Second Life is free to all users and this allows full access to the grid. If premium membership is needed then payment is required on a subscription basis.
Yes, to join Second Life is free for basic membership. You will only need to pay for premium membership if you wish to buy Linden mainland or a private estate.
No, the basic game mode in Second Life is free. You will have to pay for a premium account or to buy new clothes, or change hair and skin tone colors if you want them. To get around this, create a pay pal account, but don't credit it. This allows you to get through sign up. Be ready to contact Second Life's creators if you have problems. They were very helpful when I had trouble signing up.
There is a game called istaria but you have to pay for it.