Binance is the largest exchange in the world in terms of daily trading.
You can create your account on Binance using our referral code: https://accounts.binance.com/en/register?ref=QK75JEX3
By using this code you get 10% discount on trading fees.
There you can:
Buy and Sell DOT and KSM tokens
Stake DOT and KSM tokens
Participate on Parachains Auctions, on Polkadot, via Crowdloans