I used to fold my ruffle in half to avoid hemming but to save fabric I bought a narrow hem foot (it was only $12 dollars)....since I don't have a serger
It is the closest thing I can get to a rolled hem lol. When you are putting your ruffle onto the jeans you want to put it on upside down so the bottom of the ruffle is facing the top of the pants. Straight stitch it in place, then trim the ruffle to remove some of the fray and zig zag stitch you can also zig zag over it twice. Then flip it back down, press the seam upward then top stitch. That's about the best you can do without a serger.