BoI Shop Break Down by ISuckAtMath

BoI Shop Break Down by ISuckAtMath

Assumptions:

Completed Donation Bank (999 Coins)
Average Items Bought From Shop Per Run: 2 Main Items (15 Cents Each), and 2 Consumables (5 Cents Each)
Shop Fully Upgraded
No Discounts
No $$$ = Power
Unlimited Bombs (or Shooting Bombs)

Break Down:

30 Cents (2 Main Items) + 10 Cents (2 Consumables) = 40 Cents
999 (Completed Donation Machine)/40 Cents = 24 R 39

Conclusion:

You'd have to spend 40 Cents each run for 24 runs (give or take) in order to completely drain the donation machine (or close to it). This is assuming you had the resources (items/bombs) to get the machine to spit coins out, and the likelyhood of you wanting EVERY item/consumable that you see is not very likely either. In short it'd take you a fairly long time to drain it, and usually if you are at the last shop it's always wise to donate however much you can, or just give the machine your few cents left over unless you think you'll need it.

Additional Things to Consider:

Trinkets that give money, or make it more valuable.
Items that give money back, or give power based on money.
Etc.