I always hand hem for a much better result. It doesn't take very long. Do you keep a light tension on the fabric as it goes through the machine?

A walking foot and reducing the presser foot pressure if possible. The feed dogs move the fabric along the bottom and the walking foot will help move the top fabric to match.

The excess fabric is because the pant leg is wider at the bottom. If the hem is more than just a tiny one, this material collects.

You can run a basting thread and ease in the excess, matching aide seams and center front. With some materials you can shrink the excess out with steam. And some people make a tiny dart.

For $60 pants, I would hand-hem them with a "catch stitch", easing in the excess. The visible machine sewing looks unstylish to me, and pants hems are not a big project.

https://www.craftsy.com/blog/2014/12/flat-catch-stitch/ 

https://blog.colettehq.com/tutorials/5-ways-to-hand-stitch-a-hems

Agree with doing it by hand. I'd spend more time trying to make the machine hem look good than it would take to sit in front of TV during Big Bang Theory and do them.

I like to serge the lower edge of kids plants and hand hem catching the serged edge. For dressy pants, I like some wide ribbon sewn over the lower edge half way and the other half extending past the raw edge so that when you turn it up you catch the edge of the ribbon to the pants fabric.

You might try machine basting it first, easing in the fullness evenly around and breaking the stitching where it puckers and smoothing it out. Handsewing is probably faster.

Camille Hurst, you are a life saver. I never thought to open the side seams and it's so extremely helpful :)

" By the time I get back to where I started I always seem to have a bunch of excess fabric that puckers up." I had assumed it was the bottom edge that was too wide...that's what you get for assuming.