Really budget bike bag

I’m attempting to squeeze my Cotic Solaris max (and a load of other things) into our Audi A2 next week. It does fit with wheels off, but I thought it might be a good idea to get a budget bike bag to try and prevent drivetrain/upholstery incompatability scenarios. Have seen this on Amazon, and just wondered whether anyone has any experience of it (or similar). I really just need something to stop dirt and oil transferring from bike to car.

Would be a pain I the arse having to remove the bars and mech every time. If it’s just for keeping the car clean, mattress bag? Or a bike sock?

I’ve got something similar for the same reason and it works well.

I’ve never taken the mech or bars off, normally I just zip it up with the bars poking out (they aren’t the muddy bit).

I got one of these

https://fawkes-cycles.co.uk/search/vk

Tarpaulin might work just as well.

Old double duvet cover or sheet. If not one n the house try a charity shop. I’ve found an old sheet good for this job. When it gets clarty just bring it in the washer and it’s clean again with no hassle (note: the washer won’t remove enough stains that you’ll ever want it on your bed!)