I bought a RS TRC-458 Navaho base station at a garage sale this weekend
for
ten dollars and I have a twenty foot mast and I would like to build my own
antenna, to save $$$.

The pattern needs to be at least 180 degrees as I live on the coast of
Florida. I plan to run barefoot (till I can buy some power) so I need some
efficiency.

if you're interested in saving costs, antenna gain is way less expensive
than amplifier gain.

a simple dipole would be a good start, two 10' wires, and a balun.
suspend from 10' poles in the yard, and trim the wires to best match, or
best resonance, if you can borrow an analyzer.
people do it without the balun, but it's no longer a dipole, and the
radiation pattern is different.

a two element beam can be made with wire, if you don't have to turn it.
it's not too directional, but it may serve your needs.

a full wave loop is another low cost, gain antenna. a bit harder to support
though, since it's 9' on a side, and ideally should be vertical. this is
another one that wants a balun on it's feed.