yard sales, thrift stores, closet, friends, etc for fabric. ($'s varied, but can be free if you raid your closet and ask your friends to donate)
scissors
thread
marking tool (seamstress pencil or whatever they are called)
ruler
sewing needle
I would say these are the very basics, when I made a quilt (the only one I ever made) years ago, that was all I had... (except I purchased the fabric)
now if you wish to be using more modern tools, I would suggest a good self healing cutting mat, scissors that you use only for cutting material, rotary cutter, thread, sewing needle, seam ripper, pins, safety pins, ruler (the bigger one, don't know the sizes)
as for cost, it depends where you get the stuff... I actually found a ruler at the thrift store (well mother in law found it hehe) for 1.00 on a 50% off day, so it was 50cents) it is a 6 by 12 or something like that.
it all depends on what you want to spend, and what kind of tools you want to use
my stuff was purchased for me, so I am not sure of the total
ps the quilt I made years ago was all done by hand... eventually I had to purchase the batting, backing, and a big hoop so I could quilt it... would I do it that way again... nope
Can't wait to get the boys' rag quilts done so I can work on a quilt top