I think the question is one of material cost. What else is needed, other than the template. If so,
For an HO switch in the #6-#8 range, you'll use about 1.5 to 2 lengths of 3' rail, and about a 6-10 ties per switch, a modicum of solder and flux. I'll leave it to you to do the math, since price varies by the code of rail, etc., but it's in the ballpark of about $2-4 per switch.
Tools you'll need (that cost can be spread out over the number of switches you make, just like the template) include the files, rail nippers, and pliers, etc.
Then, there's the intangible: the fun you have making switches. That's priceless.
- Thomas