I was going to say, parking meters aren't free on Saturdays (would be a bad move on Ann Arbor's part since that's football day).
The cheapest place to park in the area is the parking structure on Washington to the west of State (I don't remember its exact address, but it's a block north of Digital Ops, I think on Washington/4th). It's $2 for the whole day. I know there's another one on Ann/Ashley that's about the same amount, but I don't know how far away that is.
It's a decently long walk from there (~20 minutes), but having a flat price is very nice in my opinion. You could also park in the parking structure on Forest Ave (between S University and Hill), but it isn't anywhere as cheap. I tend to park in the one on Forest so I don't have to go out and repay for parking at meters. Plus I don't have that much change on me. A good road to park on for available meters, in my many experiences on campus, is either Tappan or Oakland. Just keep your eyes open, basically.
I'll get more details, but I'll post this before my computer freezes again.