I suspect a lot of folks use tinfoil, because they feel it is safe, which it is and they feel it is cheaper. Definitely much cheaper than Wilton's that is for sure. A bit cheaper than floral foil too. But the thing is, some foil wrapping papers are pretty cheap too and some have nice designs. Sometimes after Christmas you can get some terrific deals on foil wrapping papers in the huge rolls, perfect for your largest boards. For smaller boards, you can use lots of things from the dollar store. Sometimes fabric remnants are really cheap, I got 60 inch organza for .75 a yard. Plus it is washable and re-usable. Some folks use white freezer paper, not my choice, but it works for a lot of folks. I have used crushed velvet and moire and dozens of fabric scraps. Paper wrapping paper with the top covered with clear contact paper.
This is just my opinion, but I think the board is every bit as important as the cake and the choice of covering makes a huge difference in the presentation. Just as a stand for a wedding cake makes a huge difference.
I recently did a simple sandcastle cake. I used brown paper to cover the board and covered over the top with plastic clear contact paper. It blended in better than if I had put the cake on the typical Wilton silver foil.
One thing that bothers me is when people put a 50 anniversary cake with all gold trims on the silver foil covered board. Just a pet peeve of mine but Hallmark makes a huge roll of gold foil, it is cheap when you consider how much foil you get.
Tissue paper is very cheap and so is clear contact plastic, you can get them at dollar stores. Patterned vinyl contact paper is also very cheap, again available at dollar stores and generally sold as shelf liner. You can buy huge rolls of vinyl, called oilcloth in some areas, that is used to cover picnic tables and such. Very cheap and washable. Cheap plastic shower curtains can be cut up to cover many boards too.
Ribbon. lace, cording and braiding makes a nice trim along the edge of your covered boards too, really dresses them up.
When you are fancying up the board, take that into consideration as part of the cost of making the cake so that you get your money back.
Hugs SQuirrely Cakes