Bellringing is traditionally run on a shoestring. Pretty much everything we need to pay for, bar major repairs, is covered by tower donations from visiting groups, practice donations, wedding fees and the church (incidentally, perhaps the "going-rate" for all sorts of donations needs reviewing - materials for repairs are much dearer, but I doubt fees and donations have increased in the interim). Perhaps we ought to check our reliance on the church to subsidise the exercise - it's £170 for a peal at one private tower currently!
As
@John Harrison mentioned, time cost is the big cost, and is often overlooked. From my perspective as a learner, I really need two practice nights a week, and general practices tended to be a bit of a waste when it was one go at rounds, then sitting on the side for the remaining 1hr20. Even in London, finding a tower where I can actually progress means travelling quite far - a good practice could get me travelling on three buses to my destination, costing me money for the fares and time (I can easily spend 2-4 hours just on travelling to a practice). I could go to the tower at the end of my road, except it is silent now. This is a barrier to progression - young people in particular are reliant on public transport or lifts from others, which means any sort of distance incurs time and monetary cost penalties. People have other things going on in their lives, and taking out an entire evening multiple times a week is not going to happen.
From my perspective as treasurer, I really want to send some of our members on ART courses so they can lead and teach handling. The course tailored to university societies is in Bristol this year (so further away from most university societies than, say, Birmingham), and train fares + accommodation + course fees take it up to a cost of over £120 per person. I can only afford to send one person, but we rather keenly need to send two. Therefore, the cost stunts both the number of people able to teach and keep the society afloat, and the skills of our ringers who could go out to make very fine leaders wherever they settle after university.
From my perspective as a tower officer and a service planner, the time burden is also on the teachers and leaders. The first type is the Respected Leader. They become known for being the person who always steps up and is good at what they do. They train up people, act as tower captain, become a district officer, try and set up clustering, fill in last minute at peals and weddings, etc. They carry too heavy a burden, such that they burn out due to the emotional, time, and monetary costs, causing the numerous responsibilities they hold to fall by the wayside. The second is the Firefighter. They are filling in all over the place because there is no-one else to take their roles on. Their cost is that they're too stuck with just trying their best to resolve immediate crises, with the opportunity cost of their own development, and maximising their time.
Overall, I'm not sure that quantifying the cost of providing tuition is helpful in itself, but we do need to identify where we can cut the costs of taking up ringing, cut the costs of providing ringing locally, and optimise the use of our money to provide facilities and trained leaders which improve the cost:benefit ratio of both providing and undergoing teaching.