Museum exhibits are expensive. Their cost is measured by the square foot, and can easily range from $100-$1000 per square foot. That means a single exhibit can easily cost in the tens of thousands of dollars.
One of the goals of this project is to make an extensible exhibit that is flexible enough to fit within any budget and capable of growing as funds are acquired. Because it's open source, it should require less engineering, and should be easier to build and maintain.
That said, material costs for this project are not insignificant. The wall mount will be a couple hundred dollars, and each cell is roughly $50. For the museum that this exhibit will go in, we have room for 60 cells. That's $3k just for the cells, and a few hundred more gets us a decent chunk of change. Unfortunately, the museum told us we had a budget of $1200. Yes, this is ridiculously low. There's no way a museum exhibit can cost that little and still look good.
Fortunately, we don't have to populate the whole thing! We can build only a few cells and drop those in, and as we get money we can add more cells and it won't hurt the look of the table at all. What's more, we could do sponsorships! We're planning to do a bit of a fundraiser, and call on the local construction and engineering firms to chip in $100 per cell to sponsor one. It's a tiny amount for them, it covers costs, and they get to sponsor something in a museum. Win win.