I use the "Little Green" Bissell machine on my SUV once or twice a year depending on how ambushes I feel. I vacuum it first then use the machine with a quality solution mixed as directed, on the carpet, seats, doors, and headliner. I got mine at a thrift shop, I have also seen them at yard sales. It works to get the dirt out, some of the stains do not come out. The have been there since I bought the SUV and the do not come off on my clothes. Seat covers are a good idea but will not cover up the dust in will aways be there cleaning it is the only way to get rid of it, and it will be healthier environment for you "no cold/flu germs around". A detailer whom you would pay to do the some might have some tricks of the trade to get some of the stains out that the normal person would not know about, If your vehicle means that much to you and are the type of person that wants it looking clean all the time then it might be worth it. On the other hand if it is just a vehicle to get around and stuff and you can put up with alittle bit of dust and dirt and do not want to be cleaning it all the time, Then cleaning it your self with some sort of machine either rented or bought at thrift shop although the job might not be perfect but at least it will be cleaner then before you started, the effort is worth the time, from time to time.
What was that my mother used to say "Cleanliness is nexted to Godliness"
Yeah Yeah Yeah If you don't like it stay out of my vehicle. I will clean it whan I want to not all the time I have a life.