I really like the Creative Grid rulers too. But your question was how to save on buying rulers......I have a credit card that gives me points on Amazon. Amazon sells Creative Grid rulers and when I learn about a ruler that I want, I use my points to get it for free. I use this card for gas, on line purchases, I pay large bills like car and homeowners insurance with the card, and other things that I would have to buy anyway, why not use the credit card and get those points. The points accumulate and soon enough I have enough points to get what I want. In fact I just "bought" 3 Creative Grid rulers that cost about 60.00 with my accumulated points and they are on their way to me for free. I pay off the card each month, so I don't incur interest, I look at it as a "win win" kind of thing.
Something to look at if you use a credit card and shop at Amazon.