Crypto rate is almost same on all exchanges. There is little bit up down based on buying and selling order so you can check price of all exchange and by them.
Another option is there are many site gives you crypto currency you have to just complete some task like musig.io where we can earn crypto coin by just answering people. 

Also you can start mining there are many types of mining, mobile mining , CPU mining and GPU mining if you have one of that machine you can earn free crypto by mining coins at home.

Also you can by some crypto when market is crash.buying crypto in red bath is always good deal. That time is best for buy coin at cheap rate . I think this is best time to enter in crypto market.