A box of dowel pins from McM is damn near free. If you need dowel pins, buy dowel pins. There are some things you fudge, and then there are things that are just so cheap that there is no point in trying to fudge them.
Though endmill shanks make really good dowel pins also. +.0000 -.0002, I'm OK with that. Nice and hard, HSS or carbide.
If you're looking at an oddball size for your fixture, gage pins. I consider gage pins as a consumable. In the 1/4" range, they are a few dollars a pop. You can't make a .226 pin cheaper, I guarantee that.
I guess it depends on what you need to do with the dowel pin. I'm not making molds, but I do make multiple piece fixtures and I dowel them together. .2505 reamer, and I used to use a .2495 reamer on the press side, but I decided I was lazy, so now I just use the bigger reamer and run a 1/4" form tap down the hole I want to be a press. Much better than the "ball bearing" method.