I like Kutter's tool.

What I did for a wrench (before I started acquiring metal working tools) was simply cut the exact right shape oval hole in a sturdy piece of 1x6 x 24" (or so) hardwood. Then use it like Larry's adjustable wrench. You'll eventually split it but it only takes a few minutes to make. This tool would be silly for a real smith but you'll probably only need it twice.