I went to my work to check out the letters we had that could fit the bill. The ones we had was about $3-4 a piece that was large enough (not really made to cover up). Then the ones like Jen had in her blog post we had, but they were too small. I wasn't that happy with the letter choices, also I'm kinda broke. I had to take a cheaper route.
I forgot how hard it was to cut foam board. I had a project in my 3D Design class where we had to make a dog sculpture out of foam board. That was easier since most of the cuts was straight not so curved. Here is a picture of that project. Yeah, that was hours and hours of work.
It is also hard to cut these letters out since our craft room looks like this. Not much room to move around.
Once the letters are cut out then you can do the same as Jen. Wrap the letters with yarn. I chose to do mine as candy corn letters. We have the warm colors in our color palette at our house. So I did one white, orange, and yellow.
It now adorns on top of the dresser in the kitchen. I spent maybe $5 on it. I already had the white and yellow yarn. All I had to do was purchase the foam board and orange yarn. I was able to do one letter a night while watching tv. It's very time consuming but not hard at all. Just sit down with a movie or a night worth of DVR shows and just get to it.