Zero, you can earn some sats per month but even then its almost nothing and may not meet a withdrawal threshold. The efficiency is amazing for the current drawn but there is no way you can get your money back from it, unless Hal want to help you out from beyond the ether.
Discussion
I was thinking more if I was to set one up in a country with A LOT of sun, so, free electricity essentiall, which might be an option for me.
Its very low in terms of wattage I was wondering If I could run one off a Peltier system from the woodstove again not an efficient use of money spent but I thought it would be fun to do,