Honestly I'd assume it'd sell for $1k+
Each of the 9 blanks (unless I miscounted) is gonna go for $100, as other mint blanks have, and the skull is probably worth at least $100 too.
generally only collectors will want all 9 specific keycaps though, so you unless you can find one, then you have to discount it to sell it as a set. one guy couldn't sell his set for $850ish a few months back, and i doubt much has changed since then, so the only real way to get that kind of money on it is break it down into smaller sets (skull, esc, wasd, arrows) and sell them individually. even then, there can be massive discoloration on the wasd (and sometimes the arrows) from finger oils, and the mint color is easily affected by light in general, so most of the existing sets are fairly devalued as a result at this point.
the real range is probably 550-750 depending on day/time, and since we're heading into the period when people tend to want to spend less money on keyboard hats, the 600 area is a pretty reasonable expectation imo.
