please tell me what is the difference betwen STEEM POWER , STEEM , STEEM DOLLARS and Estimated Value ?

Please tell me what is the difference betwen  STEEM POWER ,  STEEM ,  STEEM DOLLARS and  Estimated Value  !

i have until now  Estimated Value  $109.07  When i can cash out my earning to my wallet btc or paypal ?

• Thanks for all who answer me and this is the best answer by  villagetrading  :

STEEM POWER is like shares in Steemit - they grow over time. STEEM is the basic crypto currency and STEEM DOLLARS are yet another currency pegged to 1 USD.

I think this is the most complicated part about Steemit. I wouldn't worry about it personally as the designers of Steemit have worked out the economics. If all you ever want to do is convert to btc then you probably want to convert your earnings into STEEM and withdraw to an exchange like Bittrex

thanks  villagetrading