We recently had a problem with our basement floor drain backing up when we took a shower or used the washer. We paid $350.00 for someone to come roto-rooter the main sewer line out to the street. He used the trap next to the basement stairs inside to clean out. He pulled out a ton of roots and ran a camera through the drain. We have a clay pipe that is coming apart at a seam from the other somewhere in our front yard. We know eventually we will have to have it replaced.
So for about 2 weeks everything was fine, now there is water coming up again in the basement floor drain and about a cup of water comes out of the clean out trap where he got the roots. It only happens after running the washer (not the shower) and drains right back out of the floor drain with a loud gurguling sound. My husband cut the bottom of a bucket out and siliconed it to the floor to keep any water in the bucket and not on the floor.

My first question is: Is $4000-5000 a lot to have about 50 feet of sewer line replaced in our yard? (We think the plumber WAY over charged and overestimated us)

My second question is : Why was it OK for a couple of weeks then started happening again but this time only with the washer?

3rd question: Could one of the roof vents be blocked causing the gurgling noise?
ANY HELP greatly appriciated! This is our first house and between the plumber and car problems we are going insane and broke fast!