You can get by with one ruler for cutting strips and one for squaring up your blocks. The 6X24 is a very popular size because you can cut the full width of fabric with only one fold. The 12.5X12.5 is the best size for squaring blocks IMO. I have the 9.5X9.5 12X12 and 15X15. I use the 12.5X12.5 most of the time. I also use my 6X12 ruler a lot for subcutting strips and smaller pieces of fabric. I just don't like deaing with that large 6X24 when I'm working with smaller pieces.
Joann's has both these rulers (and more) on their website. Here's a coupon code to get 50% off one item at checkout. I don't know if it takes the 50% off the most expensive item or the least expensive though.
http://www.joann.com/joann/search/se...arch%253Druler The rectangular rulers are on page 4 and the square rulers are on page 5
Enter this code at checkout: TTF97