Austin Tollway Penalties?

[InterstateNG]

After driving 600+ miles in a day on my way to the West side of Austin, I'm not real interested in dealing with the I-35 bottleneck.  I'm looking at 45 to Mopac to avoid the mess, but I don't have a TxTag yet.  How bad are the charges for someone without a tag?

[texaskdog]

I live on Wells Branch in North Austin.  The only tolls you deal with are on 45 and the stretch of mopac to schofield.  not bad, but if you dont want to pay at all, take 35 to Howard Lane.  Turn right on Howard Lane, which turns into Schofield Pkwy.  When you hit Mopac, you'll enter it right when the tolls end.