[RPG] ny way to reduce the Essence cost of cyberware

You're absolutely right, MUDs/MUSHs tend to low-ball players on cash in an effort to slow growth. In my experience running and playing in Shadowrun I've used two different scales:

1. For high-power games with lots of cyberware, big guns and tons of excitement a normal run nets out around 10,000-20,000 'yen per player, usually leaving the group with enough cash at the end of the game to make one big purchase or several little ones. Most players found this satisfying as they then felt that you could actually get decent gear after chargen.

2. For more gang-level gritty games where players didn't start off with a lot of cyberware and couldn't buy every gun they wanted we tended to keep things much lower. 3,000-5,000 'yen per player was about right for a good run, but in order to keep the flavor there were also a lot more sessions when the runs didn't pay at all.

So, while it does depend on the tone you want to set, those are some guidelines that worked well for me in practice.

It is very difficult to increase drain resistance. You have identified the likely routes, with the potential extra option of a Mentor spirit, drugs to ignore the pain, or 'ware to soak the damage.

From here:

All magicians use Willpower plus another mental attribute appropriate to their tradition to resist Drain.

The base Drain Value for Spellcasting is listed in the spell’s description (see p. 195.) For Summoning and Binding spirits, the Drain Value is twice the number of hits (not net hits) generated by the spirit during the Opposed Test. Each hit on the Drain Resistance Test reduces the Drain Value by one. Any remaining Drain is suffered by the magician. Drain is usually Stun damage, though there are situations in which it can be transformed into Physical damage (see the Sorcery and Conjuring sections).

Therefore there are two routes to reducing drain, increasing attributes or cheesing the opposed test.

Now, Mentor spirit with spirits of man (according to this) may modify that test. (support here).

In the same area, they suggest better living through chemistry:

Buy Stim patches that let you ignore stun damage modifiers (No-Pain is even better)

From the same source, they note that you cannot use foci to resist drain:

Errata clarified that NO focus can help with drain.

Sacrifice does seem quite useful:

Sacrifice requires two Complex Actions completed consecutively. Taking any other action between the two required actions will negate the attempt. The initiate first performs a normal melee attack using the appropriate melee weapon skill. The target may attempt to parry, block, or dodge as normal. If the target is restrained or prone, appropriate melee modifiers apply (see p. 148, SR4). While any living creature can be used as a donor, the blood of sapient donors (metahumans and critters with the Sapience ability, such as sasquatches and dragons) is more potent. For each box of Physical Damage inflicted on a sapient donor, the Drain in the subsequent action is reduced by 1. For non-sentient critters, the DV is reduced by 1 for every 3 boxes of damage (possibly less if the donor is significantly smaller than an average human). Spirits can never be donors, even if they are currently possessing a living body. An initiate may use himself as a donor, drawing on his own life force to reduce the Drain of his spells. A blood magician can inflict any desired level of Physical damage on himself. Sacrifice is the prerequisite for a number of advanced metamagic techniques.

This neatly reduces the utility of the "Bag of Rats" and causes some interesting moral problems. On the other hand, it also doesn't require the death of the target.

This is absolutely the way to go if you're the kind of shammy who summons a big expletive spirit at the beginning of the day and has it hang around. I get the sense that in-combat summoning is kind of inefficient and difficult in the first place.

This page suggests some 'ware alternatives:

I wanna make a hermetic mage with the restricted gear quality and Pain Editor cultured bioware for an extra die to my drain pool and to make it so he doesn't pass out unless he's dead. Is that cheesy? Of course, I know it would be up to my GM, but I am just wondering what the general consensus is on that combo. I was also thinking of getting Cerebral Booster, but I didn't that that was cheesy because it's pretty common.

But that is a massive sacrifice...