Check out RAB Tools on Etsy. They have a line of MFT accessory items. I have several and they are really well made.
The guy charges $40 for a single bracket that holds two elemental clamps. $40
I agree that it's expensive but at the same time, by having a store on Etsy, I understand why he does it. Etsy has the advantage of allowing a lot of people to discover our products but the fees are over the top. They charge so much that in this case, I don't know if it's free shipping but if it is, I guess that on the 40$ sale, around 20$ will go to Etsy fees. On top of that, if the sale has been done by an external advertisement (ex. Facebook or Google ads), they charge an additional 15% commission fees.
For example, I sold this week a small MFT drilling jig for 40$ on sale. After all the fees (I didn't have external advertisement commission fees) and shipping to pay, I had 20$ remaining without taking into account the material fees and packaging.