Do you pay real money in second life

Yes and no.

You can work in second life to earn linden dollars, however the gross of the ppl invest REAL cash to play. See it as a game of poker with your friends then you layout some playing cash to win the pot.

In second life you can buy allot of items out of shops but also the marketplace. This offcourse needs to be paid in cash (L$) that you eaither earn in the game or simply use paypal/bankaccount to convert real life cash to L$.

You do not have to PAY to play second life, and investing in SL can be done in countless ways with rl cash or inworld earned cash.

So it is pretty double, yes can use REAL money in sl , and NO it is never a MUST or needed to use the game or have fun for that matter.