I ran across a font that some one created out of three different fonts. It's surely custom as you suspect, but could be recreated from;

Ruca
http://myfonts.us/td-GAb2qH

Engravers Old English
http://myfonts.us/td-1o6oGO

Xanthippe
http://myfonts.us/td-YPV79H

with a little hard work

How can I make a font taking individual characters from three different fonts? I am not technical and have never done this before. What software must I buy to do it. I don't want to spend fortune for software I would only use once.

It is illegal.

Alright. I'm assuming you want to make this font for personal use only and are purchasing the other three fonts. Anyway, Fontographer is really cool software. Although pretty expensive. What you would literally do is copy and paste glyphs. I'm sure there are some pretty good freeware font editors as well.

For the font editor softwares : http://www.dafont.com/soft.php#3