You can buy EOS from Exchanges now but it's better to wait if you follow EOS community and founder of EOS Daniel Larimer on Twitter than you must have got information about EOS technical flaws about its constitution arbitration and recently some accounts were freezed on EOS blockchain. They realised their mistake to give more powers to arbitrated and now they want to change constitution to make it more decentralised. All this thing's makes EOS mainnet failure and this can drop EOS price in upcoming day till their constitution 2.0 gets ready.