For me the DeFi was the best discovery of the last year.
The transaction fees can be very high if you are providing liquidity in Uniswap for example, because they are based on the ethereum network.
There are many more options such as Cakeswap that is using the Binance Smart Chain network ... the rates are much lower and it is ideal for small investors like me.
I am currently working with PanCakeSwap and Beefy.finance and in a month I have been lucky enough to double my investment.