I use a Harbor Freight wood working vise, though it seems to have been discontinued. It was about $20 and looks like this:
View attachment 364244 It's apparently been replaced with
https://www.harborfreight.com/7-in-carpenters-vise-58980.html, which may be a better unit overall, but costs a lot more.
Wood working vises are intended to have inserts (typically wood) screwed in. I have 3D printed some inserts, so the idea is the same - the inserts are soft enough to not mar or damage the item being clamped (in this case, metal barrels, stocks, etc.).