This thread deliberately contains no numbers from the server, because
generator tiers and prices are not documented officially and a made-up table
would be worse than none. What it contains is the arithmetic to use once you
know your own numbers.
The only question that matters
How long until this upgrade has paid for itself?
payback = cost / (new income per hour - old income per hour)
If an upgrade costs 1000 and moves you from 100/hour to 150/hour, it pays back
in twenty hours of that generator running. Not twenty hours of you playing —
twenty hours of it running, which is a different and much better number if
income accrues while you are offline.
Work that out once for each tier and you will have a table that is right,
because you measured it.
Wide before tall
Two cheap generators usually beat one expensive one early, for a reason that
is not about income at all: losing one costs you half, not everything.
Concentration is efficient right up until the moment somebody takes it.
The trap: buying power too early
Something that fights produces nothing. It protects what you have, which is
only worth doing once you have something worth protecting.
The instinct to buy gear early is strong because gear is what you lose when
you die. But dying with a small income and no gear costs you an afternoon.
Having gear and no income costs you the entire run, because there is nothing
generating while you are not playing.
When to stop reinvesting
When you can no longer hold what you have. If you are being taken from faster
than you are earning, another generator is not the answer — a better position
is.
That is usually the point where this stops being an economy game and becomes
a KoTH game.
Measure, do not guess
Note your income, buy the upgrade, note it again. Two numbers and a
subtraction beat any guide, including this one — and unlike a guide, they
cannot go stale on you.
If you work out a real table, post it here. That is the thread this category
is missing.