in bmx u can get mongoose diagram
The price of cycles increased liked any thing. Only good International brand that you will get is RockRider 5.1. If you want Trek, Cannodale, Merida, or Binachi you need a minimum of 23k - 25k
Why to go for any international brand when you have good indian brands available. I was with the same requirements as you are and my friend only suggested me urban trail bolt 26. It was well in budget and am enjoying it.
ya gud cycle and suggest me some more cycles
Assembling your own bike is going to cost a bomb. You need atleast 50k for that and even so you won't be able to build a bike as good as what the manufacturer is offering at that price range.
Unfortunately, bicycle prices have risen steeply due to increased taxation from the government. You need to shell out atleast 25k for the bicycle you could get for 15k a year ago.
If you want to use a bicycle for "stunting", buy a BMX. Mongoose has good ones around the 25k range. Always wear a helmet.
And don't listen to Aniket. That jackass goes around telling people who want a road bike to go for a full suspension MTB. He is merely advertising the "Urban Trail" brand, which, frankly, is neither urban (read trendy) nor trail-worthy.