am a beginner ..so can someone suggest me good exchange to buy ERC20?
Convenient and easy way is to use Bittrex.
More comlex but more profitable way is to use EtherDelta.
Yes, EtherDelta is more complex even if I have not yet tried to trade my ERC20 token there. The way I lokk at the platform, User should familiarize first before getting engage in trading. Good luck.