Wow! interesting... since I just ordered a few carrier sheets for my Titan2. I had the same problem and have wasted many 12x15 sheets trying to get the graphics as large as possible... only to watch it eventually bind up... very frustrating. My wife has a Cricut and I love their concept of the carrier sheet since you can use small scrap and waste so little. But I searched the whole Internet and wasn't finding much info for larger format cutters with carrier sheets. Nothing on youtube either. So i was really skeptical when I seen them on uscutter. Didn't even see anything on ebay for carrier sheets except for the small home project cutters. I can't wait to get mine and finally be able to cut the 12x15 space and not have to shrink the graphic down to a 9x11. that is a a lot of waste! Maybe I'll make a video and share it on youtube if this works out... lol.
I don't do koolies, but when I decide to try something new in my small business, I shop around to see what others are charging first. My most favorite place is etsy.com since they cover just about any type of craft project. I went to etsy and just typed in 'koolies' and here was the result. Etsy Koolies Considering their build-cost is very low... I would think 5 or 10 is appropriate. Of course you never want to get into the habit of over or under charge.