I recently finished our sandpaper letters and numbers for our preschool on the Range. These letters provide a tactile aspect to learning letter sounds and tracing the letters correctly helps provide an introduction to handwriting. First Son taught himself the alphabet using an alphabet puzzle (that boy loves puzzles!) and I'm hoping these aid First Daughter in a similar way. Even Second Daughter should like playing with the sandpaper (under very close supervision, of course, given her capacity for destruction).
I photocopied the letters and numbers from Teaching Montessori in the Home: Pre-School Years and then used the copy to cut them from sandpaper Kansas Dad bought for me at one of those superstores (five sheets for about $2.50; I think I used three of the sheets). The cutting definitely took the most time and aggravated my tendinitis. I probably spent at least three hours on the cutting, but I cut while watching our Netflix videos. I set them aside for a while before pasting them onto poster board. I'd recommend you store them under some books if you wait a while because some of the bends made it harder to paste them down. The poster board squares should be 6" x 6" and I did use a ruler, but I figured close counts so I just roughly measured and they look fine. I spent more time making sure I pasted the letters to the same (matte) side of the poster board, because I knew a difference in gloss would bother me more later.
By the way, apparently rubber cement is practically a controlled substance. Kansas Dad bought it for me and said he had to ask for it and it has warnings in huge letters that you should avoid using it if you are pregnant, might be pregnant or are thinking about becoming pregnant.
First Son helped by handing me each letter. We used the opportunity to talk about the letter and what sounds it makes and (as First Son says) what "it starts with" (as opposed to what starts with it). I finished the pasting on two separate days (about an hour each) when both daughters were sleeping at the same time.
This was a very inexpensive, but time-consuming project. We bought the poster board at school supplies sales, so it was very cheap (though it would have been even more so if I had bothered to calculate how much I needed before the first sale, which was better). Some of the later projects are simple enough for an older child to handle (which I think would be a wonderful way to involve siblings), but cutting sandpaper is a bit tough and the pasting would have to be done under strict supervision or with some less toxic substance, or both.