I made one for my DD that was 26" and another that was 28". I prefer the 28". I might try a 30" or longer because I like the way the dangling ends look. I don't sell them so if make them longer than most it won't be a loss as far as cost.
I have also read somewhere here that they are sold 1 for $3.00 or 2 for $5.00....someone else sells them 3 for someother price and she said she almost always sells them in 3s.
Hope this helps and good luck selling