How long will it take to see results?
join a mma gym,no, you wont have to fight anyone, its all you will need, weights are for meatheads, a good trainer will wear you out, you will have results in one session mentally, (once you feel what it takes to drop weight) if you can take two classes a week, you will see it soon
Running, Push ups, sit ups... Squats Cheaper than a gym and more natural way without strain They say 21 days forms a habit so if your persistant after the 21 days you will automatically do it as a routine.
buff? easiest way is to wait off until your 28-30 because at that time your body naturally increases in size otherwise its nonstop protein shakes
Pushups, they work more then half of the major muscles in your body. If you actually keep a solid schedule (4 days a week) then within about 2 months you would see result. I would reccomend you to get some free wieghts though. They help the best for your arms. If you used those correctly you would see results in tone and strength within 1 or 2 weeks.