Macros

[scars]

Hello all,
I know there have been already thousands of discussions about macros,
but I can't remember what the conclusion was ^^"
so what do you think about the PENTAX K VIVITAR MACRO 2,8/100? How much
is a reasonable price for it? (at ebay, no professional foto dealer)
There's als a   PENTAX SMC-M MACRO 4.0/100  up there.
I have a pentax ME and a MX, so I don't need AF lenses and I can't spent
too much money...
Thanks for any advice.
Bye Katrin