Try sending them Bitcoin from exchanges that do not charge transfer fees - for example: GDAX.
Lending sounds great. However, giving away 15% to Poloniex, then 10% to a bot means only 75% for me.
Not using a bot is cumbersome and time consuming.
In addition I have another worry: Keeping larger and larger amounts on Poloniex isn't a wise idea.
So for me, lendig is more like a pastime and not investment.