I think this is truly strange if one question is USD 40! I've never heard such a strange thing in my life. I would advise people to be cautious of teachers that would demand $40 per question. Most people who come to Geshe Sonam for advice do not pay anything, some leave an offering of their choice because they want to. But it is very clear that interactions with the teacher are free of charge.
But yes, official teaching courses do have a suggested donation attached.. The unfortunate truth is that Westerners just do not donate to the centres. So most have to charge fees. Where I am in Europe courses are listed with a suggested donation at most of the dharma centres (not my favourite thing in the world, but I see the necessity). However,at our centre there are a number of people who pay less or who do not pay at all and instead do some volunteer work. We just purchased a new building here in the Netherlands and I don't know how else we'd be able to cover the costs if we just counted on goodwill.
My lama in Canada steadfastly refused to set any fees back in the '90s. But people didn't donate so the centre in Toronto had to close. Fortunately, the students in Montreal (many of whom were Asian), had the habit of making donations so that temple was able to remain open.
The unfortunate truth is that Westerners (especially those new to Dharma) usually don't give anything near enough to cover costs unless requested.
And when something is free, it still means someone is paying somewhere. In the case of Kechara the members seem to make very generous donations. So because of that, there are lots of activities free of charge. But I try to drive this point home- that even if you aren't paying someone else is. Because otherwise there is this naieve vision that the temple, food for the teacher and sangha, visas and travel expenses all just "manifest" from somewhere.
In order to ensure my mind never comes under the power of the self-cherishing attitude,
I must obtain control over my own mind.
Therefore, amongst all empowerments, the empowerment that gives me control over my mind is the best,
and I have received the most profound empowerment with this teaching.
brtsal ba'i bkhra drin