I haven't found a hobbie yet that doesn't get expensive. Just watch yourself!
We make our own binding because it goes with the individual quilts that way and it is of better quality usually than what I've seen in the stores.
Blenders are fabrics with texture but not much design. That are a color that goes with the other fabrics you are using ( ie it blends with them). I would suggest that you get the biggest cutting mat you can afford. When you are cutting large pieces of fabric it will help. If I could only have one ruler it would be the 6 1/2 by 24" one. I use that one the most. As for the rotary cutter, I would suggest the 45. It is up to you to find the one that works best for you though.
Hope some of this helps. These are just my opinions.