By "regular" do you mean a bed for a single person (in US, it's called a Twin bed)? If so, for quilting that is 1/2 - 1" spacing with a 50wt/2 ply thread, I would use about half a cone of Aurifil. I typically buy the large spools instead of cones & I use roughly 2 large spools for a 65x65" quilt. That's about 3000 meters of thread. An Aurifil cone contains 5900 meters. Unless you're doing a LOT of piecing, 1 cone would likely be sufficient for a Twin sized quilt (piece, quilt, bind).
To answer your question, we need to know:
1) dimensions of quilt
2) weight of thread
3) how densely you plan to quilt
4) what brand of thread did you buy