Hi Gillybean
Electro-etch kits are pretty cheap these days and almost make the do-it-yourself option unnecessary. You can also find acid etching instructions both in David Boyes knifemaking book and the "How to Make Knives" book by Loveless and Barney. I know one incredibly talented maker, Brian Lyttle, who freehand engraves beautiful script, even on small areas like the spine.
You mentioned inexpensive and if you don't want to start out with a kit of your own, go to a trophy shop (sports trophys - not a taxidermist). Many can laser fusion etch just about anything on a blade for about $10 including setup. It is durable and looks good. They will also have solutions for antler or other handle materials. Note - do not go to the places in malls that sell cigarette lighters and offer to engrave them. The machines are inadequate for knife steel and the operators are typically poorly trained.
Good Luck
Rob!