In recent months, the price of Ethereum gas has become a real problem, however by using a few little tricks it is possible to limit the damage. To do this we will use some sites. One  of the best aggregators of the various dex is 1Inch
How does it work? It takes the data from the real dex (Kyber, Uniswap, Balancer, Oasis, Bancor, AirSwap, etc), connect your wallet, choose the swap you want to make (ERC20) and the site searches for the most convenient exchange among all the dexes ( the transaction is split).

TOKEN CHI: SAVE ON GAS
This platform has also created one token called "Chi" which is priced according to the gas of Ethereum (the value varies according to the value of the gas). Through Chi you can save on the cost of gas.
If we have to make a $ 5 gas transaction, we will buy $ 5 of Chi so we hit "Enable Chi".
Thanks to this trick, 1inch will make us pay about half the gas ($ 2.50).
How is it possible? On some smart contracts, gas consumption is simply not optimized and who tries to optimize it (it is as if there were returns of the gas used for the transaction).
It is worth buying Chi when the price of gas is low and keeping a reserve. For more info: GasToken

TARGET GAS PRICE
Very useful is the implementation with the site Hal which uses a network of oracles (in particular Chainlink) and allows you to receive notifications (on Discord, Telegram, email, etc) when the cost of gas of Ethereum falls below a certain threshold.
For example, I can set up a notification, connect the wallet and automate the purchase of "Chi" when the gas drops below 220 Gwei and then speculate (selling it) when the gas increases in value (as mentioned, the value of Chi depends on gas!) .