Reddit mentions of CRL Nickel Plated Adjustable Mirror Clip set for 3/8 in (10 mm) Straight Edge Glass - Package

Do you have an Ikea near by? They have a variety of glass table tops that are very reasonably priced.

We used some big ones and just mounted them with heavy duty mirror mounts. We used 6 per table top, as they weight 80 pounds or so. We have 4 clips in the studs, and 2 using just heavy duty drywall anchors. We got the idea from this post.

The main problem you run into with mirror clips is that they are designed for a set thickness, so you need to get the ones designed for whatever glass you have as well as the weight.

We looked at getting "off the shelf" tempered glass panels, but we found that they all had sharp edges (to be used for windows, or picture frames). We also were not happy with the relative "thinness" of the standard glass, as it had a good deal of flex in it, which is bad if you are writing on it. You will quickly learn that flat walls are not always flat.

We looked into getting some made at a glass shop, but they were very expensive.