The problem with purchasing very $$$$ items for teaching HG+ children using "official" materials?
Consider how many times they will actually USE those items.
Most PG children need only a single repetition to learn it inside-and-out-and-forever.
Then your $75 item has served its purpose and is of no additional use to you.
This also goes for things which take a ton of TIME to develop, by the way. I spent MONTHS carefully coloring/creating math center boxes from shoeboxes, file-folder board games for reading...
unfortunately, my DD used those items maybe 3-4 times at most. Twenty minutes or so each. In other words, her time engaged with the center/game was frequently less than MINE was in terms of labor invested in coloring, assembly, etc.
