I don't really like the whole price break at X number of peices thing in this type of situation.
We used to order shirts and bandanas for our secular event and would order shirts by even dozens and then round up to 144 peices to get the price break.
We always had way too many left over which far out weighed the price break savings
We do it by pre pay pre order now so no more issues with that.
You might consider getting a complete cost estimate on some smaller batches like 10, 15, 20 & 25 peices with shipping.
Start pre sales at the 10 unit cost price and start taking pre paid orders Up to your posted order cut off date. Print and ship however many are pre ordered.
If other missed out and want to get some you could do another small batch if your so inclined.
Cheapers good but not at cost risk of 100, I highly doubt you'll sell that many without a lot of effort on your part.
Calanders seem to be given away as advertising a lot too.
My 02