1. do you use it mainly to make money?
I have purchased some services with my Bitcoin, and also invested them on BTC-TC to make some money, its a lot of work though. (Very easy to lose money)
2. how do you make money out of it? mining or buy&sell the coins?
I have mined about $5 worth of Bitcoin, so that is not viable for me. Mainly day trading stocks and Litecoins.
3. how often are the big jumps in value? like 50$ differences.
Not very often. When the price starts moving large like that be careful coming in and out of pairs (litecoin to bitcoin and usd to bitcoin)
4. is there any official value? or do i need to go by what sits like bitstamp says? (131$)
Value is set by the free market, meaning anyone and everyone sets the value. The equilibrium between what people want to buy and sell defines the current price. As more people want Bitcoin the price will go up because people will start selling it for more knowing that there is more demand. The reverse is also true.
5. how much money do you usually make from buying and selling? im planing on starting with a small amount. like 3 bitcoins.
My max loss in a day is 100 bitcoins and my max gain in a day is 100 bitcoins. Be very careful!
6. how risky is it? its not like the value drops allot for a long time so there isnt really a risk, especially if im going to mess with 3 coins... (?)
You could lose it all day trading, your government might ban it, a fatal flaw might be found, the exchange might be a scam and run with your money, etc... do lots of research.