You don't "have to" have an accumulator to run the car with CIS. It just makes it easier to start as the car retains some level of fuel pressure in the lines. On my VW race car I have a bad accumulator and I have to turn the key to the on position and then off 2-3 times and then crank it to get it to start when it's been sitting a few hours or more.
They are expensive parts to buy new. If you go to look at a pick n pull be aware that while there were a number of different model cars that used CIS and an accumulator besides VW all of then are going to 20 years old or more.
Figure on a new one at around $100.
CIS is very expensive to get parts for.
You can run up a total well over $1000 in new parts for this FI system and still not replace all the important parts!