Summary: In a previous post I discussed the construction of charity lotteries, which let donors who think that the effectiveness of their donations has increasing returns to scale convert small donations into a small chance of donations large enough to exploit scale economies. However, transaction and coordination costs pose a barrier to individual users: there are scale economies to setting up charity lotteries. Effective altruists looking for projects could set up a charity lottery with low transaction costs using a donor-advised fund to provide easy access to small donors.