Originally posted by abacus07 ....
what happened to the OP though? He wanted cheap macro and then mentions a $500 budget.
OP wanted excellent quality
beyond 1:1 which changes things a bit. What OP judges to be of sufficient quality isn't clear either.
I get the impression that OP has limited macro experience and fuzzy goals so doesn't actually know what specifications to use other than "the best".
In such a situation a good strategy is to put a good achromatic +4-6 diopter close-up lens on the Tamron zoom to see what s/he really wants. Then s/he will be able to see if s/he can actually hand-hold shots at mags greater than 1:1, and if there is anything of interest at higher magnifications. Whatever happens in the long run, the $75 or so invested in a good close-up lens will be money well spent.
I do not recommend getting cheap diopter lenses just to try; the quality may be so poor as prevent learning much except the quality is poor.