Gun rest for sighting in.

[BrentD]

Eagle Bench Rest with leather bags, front and rear.

If you are serious...
Buy once.
Cry once.

aka, "It's the Stingy Man that pays the most" (sensu Tom and Ray).

 

[old270hunter]

I now use a couple insulated lunch bags filled with sand. They are larger than most shooting bags and seem to work just fine for me. Not a joke, I actually use these.

 

[nrpate05]

For the front I use a sleeping bag in its stuff sack and put a towel on top for a little traction. For the rear usually a rolled up jacket or something of the like.