TexasCHLforum.com

Careful with Craigslist. Quite a few people make money off of the unsuspecting... No payments up front - not for "equipment" - not for deposit - nothing... Remember, they can lien your house if you don't pay. If they don't work, it's much harder to do something about it.

I'm in the "dig it yourself" camp....

I have a friend who bought an older home in Austin and ran into the same thing - roots in the drain structure. Quotes were from $3-$5k for replacing the drain line which was around 150 feet long.
In all reality, it can be very hard to dig in certain parts of austin - a backhoe won't get it done, at least without a ram.

In my area, you bring in a rock-saw trencher. I can rent one for 8 hours @ $350. Personally, I'd offer to install the main run of pipe myself - likely plumbers don't have this equipment or mark up the service to get it done. I'd ask the plumber for pipe diameter and specification, indicate where he / she wants it. Only other question might be hitting an underground utility. Plumber does the connection at the house and at the sewer main.

Note, better (less rock) soil - you can rent a ditch-witch chain drive type thing for <$200.