Oil Paintings

Good morning,

I am new to oil painting but I'm also catching on pretty quick. I love blending the colors and find it easier than working with acrylic paints. My question for you guys are how big is the common oil painting?
My goal after Christmas is to unroll some canvas and do a big piece. I'm just not sure how big.
Also, where do you guys shop for supplies?
I normally shop anywhere but I'm looking for quality items now.

By the way the picture shown of the pastel flowers, was my very first oil painting. My second one was of a humming bird. The hummingbird was given as a gift but the picture of that one you can find on my FB or Instagram @apetersensgallery

Thank you,

Amanda Petersen