A warm welcome to the world of quilting! It's fabulous, challenging at times, but great therapy and a limitless field of creativity.
Everyone has their own answers based on what works for them. The only "stupid" question is the one that didn't get asked. So, ask away. There are so many talented, practical and smart women here that are always ready to help.
I'd approach your question to say that you should pick out a pattern first that will give you a place to start. The design of the pattern, the way the fat quarter is cut, the size and shape will all determine what you'll need.
The sale price is great for FQ's as they go for more than twice that (closer to $3 in quilt shops). If you're in a position to buy them to have them on hand or pick some for inspiration on this project, pick out and get what you can, what you love, what catches your eye. It's the start of a stash and an addiction as many can attest to here. :-) Enjoy!!!!