If you're new to quilting all the names of precut fabrics can be kind of confusing. I remember when I first heard of Layer Cakes, Jolly Bars and Honey Buns I thought it was really strange. I still have to look up the measurements of each one.
Today I'm sharing about one of the most common precuts... the Jelly Roll and why beginner quilters should use them.
The Jelly Roll is a roll of 2 1/2 inch precut strips of fabric. Each strip of fabric is 2 1/2 inch x width of fabric. Width of fabric is usually considered around 43 inches.
Generally people call these rolls of fabric Jelly Rolls, but it's important to note that Moda Fabrics has trade marked this name. Riley Blake Fabrics calls 2 1/2 inch precut strips Rolie Polies. So different companies use different names, but Jelly Roll is the most common. 
Why use Jelly Rolls?
Jelly Rolls are convenient because they are already cut, ironed fabric. All you have to do is unroll the fabric and get sewing or cutting.
Jelly Rolls are cut with accuracy so you don't have to spend time cutting lots of long strips for your next project.
Making your own Jelly Roll is definitely doable (we used to do it at a quilt shop I worked at). You just need to cut your fabric into 2 1/2 in. x WOF strips. 
I also love Jelly Rolls because you can get a lot of different fabrics without having to drop a whole bunch of cash. Buying a fat quarter bundle of a large fabric collection is expensive. But buying a Jelly Roll is a great way to get a piece of each fabric from a collection without having to spend as much money.
Many times Jelly Roll friendly quilt patterns are beginner friendly. Below you can see the Sunflower Moonbeam Quilt Pattern written for the beginner quilter. The pattern is started by literally sewing all the 2 1/2 inch strips into pairs. If you can sew a straight line, you can sew this pattern! And the whole thing uses only Jelly Rolls. 
A lot of times if I love a fabric line but don't know what I want to make with it, I'll but a Jelly Roll. This way I have a piece of each piece of fabric from the line and I can stash it away until inspiration strikes. The problem is finding the place to stash it.
Jelly Rolls are a universal quilting term. So any quilt shop should be able to help you find a pattern to go with your Jelly Roll or give you tips on sewing with one.
If you haven't given Jelly Rolls, Rolie Polies, or 2 1/2 inch precut strips a try... it's time!
Start with the Sunflower Moonbeam Quilt Pattern. It's not scary... I promise.