I know this thread was set up for customers,but I thought I'd add my penn'orth.
Like Bunny I too charge the RRP =
Soups/Shakes £1.65
Tetras...........£1.85
Bars..............£1.90 etc
On the few occasions I've been asked to drive to see a client I charge 50p a mile. This helps to cover the combined costs of the physical drive,the extra time it takes & the effort of packing everything into the car etc. Having said that, if an established client has a problem I've been known to visit for free.
I've thought about simplifying my charges to a flat rate for a weeks supply regardless of product type by charging an 'average' rate, but for the present have decided against it. The advantages include easy arithmetic, predictable costs for the client, customers can select what they fancy rather than what they feel they ought to buy etc.
However,those of my people who are on a limited budget try to keep their costs down by avoiding the 'convenience' items & it is them who would be penalised by the flat rate. This is something I shall keep in mind though. If most customers would prefer it then I guess I'd plump for the round about £37.00 mark.
Also, even though I know this was just a light hearted 'cost' census thread, I think it's worth considering what else you get from your CDC.
Availability, approachability, flexibility, time, support, encouragement, ideas, information, education, motivation, compassion, understanding, reliability, experience (I think I've made my point) or even tea & sympathy. If they offer all of these then you're getting good value even if they charge towards the upper end of the range ( but then I would say that wouldn't I?)