Vilros.com has the pi zero with $2 shipping. Most places
charge a bit more for the shipping it seems. That brings
the total to $7 for the 1.3 version (non-wifi.)

I want to build a little addition to my z80 ROM-Basic
computer. Having tried and failed- so far- to build a
300 baud cassette interface, I want to find another way
to save/load basic programs for the z80, without having
to have it connected to my PC for storage.

My idea is to build a pi-zero-based device with a 2-line
LCD display and a few buttons. Perhaps and up/down button
to select a filename (programmatically starting with "A"
and going through "ZZ" perhaps...), plus a button to 
save/overwrite and another button to load/read. The device
would be connected to the rx/tx of the 68B50 on my z80
computer directly, so it could inject basic lines, or
record them after a LIST command was issued.

I'm not sure that makes sense, but hopefully I can just
build the thing and then it will make more sense.

I'm a little disappointed because I wanted this particular
z80 build to be pretty independent of modern technology. I
suppose I can consider the save/load mechanis just a
replacement for the cassette interface. The one nice thing
would be the ability to save/load at 115.2k vs 300 baud,
though I was also looking forward to being forced to work
through a 300 baud experience.

I'll probably cover the construction of this little device
on my grex gopher hole, where I've covered most of the z80
stuff (that's gopher://grex.org then browse to tfurrows.)