5' of mesh (screen) (that's 1-2mm too wide) was under $4 so that's about 60 coils. Math tells me I could get about 450 coils out of my sheet of mesh (screen), you can get that for about $20 shipped.
The VapeFly stamped mesh is about $6-7 for 15 from China.
I doubt if it's difficult for the store to get drop in mesh coils. Maybe their supplier doesn't carry them or they don't like them.
Yes no matter how you cut it the cost is going to be less than premade coils. I would prefer to make sure that the metal I am using is of good quality and pure. I would pay more for better stuff. If I can buy mesh made in the USA I would rather do that then buy from China.
I am going to ask the manufacturer of the Themis about the mesh recommendations and using the Bacon Prime which I think is their best cotton vs cotton rectangles. The cost of the best Bacon cotton was not very much and it seems neither is the mesh. As long as it works well enough I don't see any negatives about it.
Have you got your Themis to where you like it and can get the vapor production you want? I don't see any competition out there really. I for sure want to have a tank. I have been keeping my eyes out for sales on that. I have not found one on the mesh version yet.