Cost to manufacture/distribute is often the calculation starting point
when determining final price..

Prices tend to be set at whatever the market will bear.... Also note
that those with flashy paint jobs and go-fast stripes will always cost
more! grin

Antennas designed/built long ago may have to amortise higher design
costs. Then again more sales over the years should have bought the price
down.

Quality? Longevity? Gain should not be the sole method for making a
choice of what antenna to buy. I personally would also look at sidelobe
performance (for reduction of possible interference). One also has to
calculate the path requirements and signal margins to do the job
properly. Allowing for cable loss is another biggy. Many big spread
spectrum suppliers (eg Cisco) have a spreadsheet you can download for
calculating the link budget for an LOS path.

Re increasing the gain w/out and incerase in size, generally not. If you
load the elements in such a way that they are smaller to make use of
phasing (eg a collinear) then losses are introduced as well as the
aperture getting smaller. My opinion is that you'd have better
directivity but no/little increase of gain in the intended direction.
The donut would be flatter by the way.

Would you care to explain your exact requirements? Like are you trying
for point to point links or just a larger hot spot coverage. They have
diferent antenna requirments.

Cheers Bob W5/VK2YQA

wrote:
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Also, out of curiosity, why would any one wants to pay $200 for a 3 ft
long antenna vs $60 for a less than 1 ft long antenna of the same gain,
only because the $200 is an outdoor one?