So my favorite new tool is this scoring board from Martha Stewart Crafts. I used a 40% off coupon at Michael's and was able to get it for about $12. I've bought inexpensive white card stock on sale, and using the board I can make envelopes of many sizes for less than a nickel each.
The scoring board comes with an envelope guide which fits in a little slot in the base of the board when it's not in use. So convenient! The top of the board also flips open to hold the scoring tool which is even better than the bone folder that I already own.
I recently made a little 3x3 card and needed a small envelope for it. The guide on the scoring board has measurements for a 6x6 envelope, so I decided to try just halving all the measurements. It worked like a charm!
Happy Fathers' Day to all the dads out there!