Caution, Wall of Text ahead.
When it does get to that stage, we can talk about how the factions differ (with criminals having runs costed more in terms of achieved draw quality up to that point, for instance). For now, I’d just assume assembing a rig will cost the runner about 10 credits, spread evenly over the first 6-8 turns or so. 10 credits feels about right for both Shaper and Anarch:
- Mimic, Sucker, Corroder, two Parasites for Code Gates
- Lady, Cyber-Cypher, 4 creds to get through Sentries
Criminals are a bit trickier (damn you, Fairy and Inside Job), but when you factor in the install clicks that could have been resource clicks, I’m guessing you come in at around 10 cred as well.
The most tricky ones to compute will be the circumstantial ones (because we can’t properly evaluate when to add an additional cost to them), and the one-use ones (because there we need to count the clicks spent installing more often). Also, stuff including heavy Parasite recursion has good potential to screw the calculations up.
Co-simulation, while being the desired final state of this experiment of course, might be overkill for what we need right here and now. I’m thinking more along the lines of “add an estimated sum of credits needed to interact with the corp at various moments”, much like we did with costing the runs. My gut says that while this money will be spent in various ways against various corps (trashes vs. NBN as opposed to more expensive barriers vs. Weyland, for instance), the overall sum is going to remain more or less the same.
Thinking about various corp decks, here’s my stab at abstracting the interactions into a general cost estimate:
- Not wanting to lose will probably cost you around 5-6 credits over the course of the game:
- Carapace for 3, clearing an inopportune Snare tag once
- Deus X twice (to eat, say, a Snare and a Ronin/Philotic)
- Non-kill decks might well cost you more than kill decks on their closing methods (repeated runs on HQ trying to fish out the agenda so they can’t Biotic it), beating Ash traces, running the server multiple times due to Caprice, etc etc), so in general I’d tend to feel safe adding this 5-cred buffer to @Nordicstrike’s initial calculation for any opponent
- Given the prevalence of NAPD Contract (and to a lesser extent TFP/Fetal/must-trash assets), I think we should assume you want to have at least 4 credits on hand when you’re done getting into the server, and that you’re not running until you can do that. The run won’t always cost you those credits, but you want to have them on hand (and spend them, say, 25% of the time, randomly)
I think just adding these two things would give a significantly improved result.
So, what you’re saying is… they’re not any more? Damn, I gotta step up my game! 
(also, thanks!)
edit (damn you, NordicNinja): I don’t buy the 7 credits. SMC costs 2 to use, Chip costs whatever you’re pulling back. Other than that, we seem to be thinking in the same general direction, though!