I only use the chinese cheapie mcns, which were about $6 each.
each wash costs us 7c in power/water/detergent (use wool wash occasionally, and our usual front loader powder)
If I used disposables it would have been around 5 per day (on special 30c each, so $1.50/day, $45 a month)
My DD is 22 months = $990 for disposables
for cloth I have 30 in rotation at $6 each ( $180) and $462 for washing so Im still at half price, and the MCNs will definitely last at least another year for bellyfruit (maybe to toilet training as well)