These would be my thoughts exactly. Personally, I'd do this for free, but that's me, not the OP. $85/hr to fly a drone around and take some pictures? Humm?
There is nothing wrong with charging for your time and work, plus there is the cost of the drone you are using, the time to do the editing, the cost of the computer and the cost of the editing programme used to edit. All these cost have to be taken into account, because all these things the OP had to lay out money, to get. He is not borrowing someone's drone, computer and editing software for free.
However, what to charge is always the most difficult thing to work out in an area where there is little competition to gain an idea of what a going rate is. If you have that, then there is also the known fact that this would be an inexperienced business operator, doing a new thing (You), compared to an experienced company doing drone filming, so you can't just use their prices as an example.
As has been said, you should probably state that you are early on in your drone business and even though you are a competent pilot, sinc ethis is a new venture, you will allow a significant discount to the person, because you would like to use his recommendation for future paying work. Therefore you will look at your very discounted price as a form of paid advertising on your behalf. That way if the person wants to hire you in the future, they will not expect you to be just as low priced.
The ongoing problem that arises from a new operator charging a low price or doing it for free, is that the customer will not only expect that the next time, but may well tell friends that this guy does it for free or super cheap, and then you get a name in the market as the free or cheap guy, which is difficult to get away from.
As has been suggested, ask what the farmer has as a budget, then tell him your price is normally more, but that you understand farmers are having a tough time under the current economical climate (be it true or not) ad that you are prepared to offer him a one time super deal to help him out, in the hopes that he sees what you can offer in drone filming, and hopes that should he have any future needs for drone filming, that he considers you to do that work.
Or you can give a set price you are comfortable with and state that this is just the job creation fee, and that you will offer the editing and final product at no charge, to help him out. That way if you get future work from the person, you can justify a higher price for a job, because you then will be including in that price, the cost of your time for editing and finishing the product. Then you can always add on more for creative titles etc. as a way to increase your income for future work from him or others who have heard about you as a result of the work you did for him.
Of course doing things for friends or those you feel have special needs, for free, is a different matter all together, and I am always up for helping others out when I can, at no charge, if you fell the need is there for such an offer, just don't make free, a habit.
