When it comes to cloaks you have basically two options, make one or buy one.
On making one - If you choose to make a cloak, you have to sew. Even I can’t avoid sewing forever. Nor am I terrific at explaining how to sew something. But I can point you at people who are good at it.
The simplest.
A bit more complicated.
One of the prettiest.
Storebought patterns - There are some really good ones out there from standard pattern companies in the wake of LotR.
Here’s Simplicity’s - 5794 (for the ladies), 5840 (Unisex cloaks and a really decent Jedi costume), and 9887 (LotR cloaks).
I would be remiss if I didn’t at least point out the Folkwear Kinsale cloak pattern, but it’s neither Cheap or quick. Just in case someone out there gets adventuresome. I have to say it’s gorgeous, and well-drawn. Yum. Want one.
On buying one cheaply - If you’re not a seamstress, let me point out that this is the Halloween season, and some nice cloaks can be had (if you’ve a discerning eye) off the costumes shelf. Pick a real fabric, lined if you can. Stay away from the christmas red lining unless you’re just set on it. Nothing screams Halloween cloak faster. Look for alternate colored linings, or just a nice quality unlined. If you want to make it look better, find a nice trim, and use fabric glue or wonderunder (a iron on fabric fuser) to attach to the edges.
I got a simple black crush-velvet cloak last year after Halloween for a buck. I intend to look for several more this year in the after-holiday sales, and paint them with fabric paint. Different colors too, since I got black last time, I’m looking for red, blue and green.