Much training in the not-for-private-profit sector has, in the past, been offered for free or at very low-cost. Of course, no training is ever free - someone has to pay for it, but it's often not paid by the trainees themselves (although there's always the cost of their attendance time and travel to factor in, even for volunteers).
This has probably undermined the perceived value of quality training and we have work to do to re-emphasise the professional and personal value of learning. Even saying "this training would cost £150 per delegate but is being subsidised by [credit funding source]" is better than nothing. A published sliding scale of charges is also justifiable - and paying at least something could help the trainee make more of their learning.
If a social enterprise is being charged £75 for a training day - affordable for most business-like organisations - a number of decisions follow. What does £75 of learning look like? On what might we spend that £75 if not training? How will be make sure we get value for money? If this means turning up and leaving on time, engaging with training, trainer and other trainees, and using the learning when we leave the training room, that can only be a good thing!
And would you perceive the quality of the trainer differently if you had paid £150 to hear their pearls of wisdom, rather than nothing? Charging for services can raise expectations and this can also help ensure quality isa maintained.