You can see your acorns at the top right of your screen, between your gold and your ladder points.

But no, I don't know what they do.

In fact there are three freely convertible currencies in the Galaxy, but none of them count. The Altairian Dollar has recently collapsed, the Flanian Pobble bead is only exchangeable for other Flanian Pobble Beads, and the Triganic Pu has its own very special problems. Its exchange rate of eight Ningis to one Pu is simple enough, but since a Ningi is a rubber coin six thousand eight hundred miles along each side, no one has ever collected enough to own one Pu. Ningis are not negotiable currency, because the Galactibanks refuse to deal in fiddling small change. From this basic premise it is very simple to prove that the Galactibanks are also the product of a deranged imagination.