Hi, building a VA from scratch is hard and takes a on if time. What I will suggest to you is following @KaiM’s amazing instructions for building a crew center ALL for free!!! Here is step 1:
Creating a phpVMS Crew Center - Part One - Setting up Hosting
I would NOT recommend airtable for you VA’s crew center, it lacks professionalism. These instructions above are great for a basis and start up crew center and it doesn’t cost a cent.
Now with VA’s if you are starting one basses off of an actual airline irl then paying anywhere from 3-15 dollars is something you might have to do. VAschedules.net is a website that has every list of an airlines flights, aircraft, and airport info for phpVMS which is used in the instructions above.
If you are making a fictional VA or something you are creating, then you probably won’t spend anything marking your VA.