Ideas for reducing Ally Spirit karma cost:

Restrict it to only having powers/skills on a certain spirit (i. e. Fire or Man)'s powers/optional powers/skills list: -20% karma cost when buying powers/skills

Restrict it to only having powers on a certain spirit's power list (no optional ones): -40% karma cost when buying powers

Negative qualities: Negotiate with your GM to give it negative qualities for a break on karma cost (only certain qualities, like combat paralysis or spirit bane would apply)

Idea for reducing Focus Binding cost:
Most of these make sense if you actually build the method into the focus; if you just find a focus lying somewhere, I dunno.

Require a sacrifice to bind it (for example, the lives of a number of metahumans equal to the focus' Force, each of whom must have at least as many physical boxes as the focus' Force)

Binding by making an extended Arcana check to research the metaplanar source of the focus' power, and completing a quest there to bind it

A less expensive "imperfect bind" might have a built-in drawback, like extra drain for all relevant checks, or an Edge test to see if it works on any given test, or it glows like a goddamn Christmas tree on the astral, or it can't help screaming sometimes.

Sorry if any of these are redundancies, I tried to slog through the previous material but it's late and my attention isn't so well focused. Good luck!

Me too...

Back in the day I let magic folks sacrifice cash/money for karma, as in burning goods to their totems, placing offerings on a raft let out to sea, what have you. (I dare say this is in an old book?)

Kept the balance pretty good, lets them get their karma, and lets sams/deckers/riggers, keep their loot.

Agreed. One karma can buy 2,500 nuYen in chargen, so I don't think it would be unreasonable for 3,000 nuYen (or an equivalent value of whatever goods are relevant) to buy one karma. Conversely, if someone were so inclined, I'd let one karma buy 2,000 nuYen (though I'd consider it a bad deal fir anyone). Keep the exchange rate a little biased, but not vicious.