  We use SDSS data to investigate the scaling relations of 127 NoSOCS and 56
CIRS galaxy clusters at low redshift ($z \le 0.10$). We show that richness and
both optical and X-ray luminosities are reliable mass proxies. The scatter in
mass at fixed observable is $\sim$ 40%, depending on the aperture, sample and
observable considered. For example, for the massive CIRS systems
$\sigma_{lnM500|N500}$ = 0.33 $\pm$ 0.05 and $\sigma_{lnM500|Lx}$ = 0.48 $\pm$
0.06. For the full sample $\sigma_{lnM500|N500}$ = 0.43 $\pm$ 0.03 and
$\sigma_{lnM500|Lx}$ = 0.56 $\pm$ 0.06. We estimate substructure using two and
three dimensional optical data, verifying that substructure has no significant
effect on the cluster scaling relations (intercepts and slopes), independent of
which substructure test we use. For a subset of twenty-one clusters, we
estimate masses from the M-T$_X$ relation using temperature measures from BAX.
The scaling relations derived from the optical and X-ray masses are indeed very
similar, indicating that our method consistently estimates the cluster mass and
yields equivalent results regardless of the wavelength from which we measure
mass. For massive systems, we represent the mass-richness relation by a
function with the form ${\rm ln (M_{200}) = A + B \times ln(N_{200}/60)}$, with
M$_{200}$ being expressed in units of 10$^{14}$ M$_{\odot}$. Using the virial
mass, for CIRS clusters, we find A = (1.39 $\pm$ 0.07) and B = (1.00 $\pm$
0.11). The relations based on the virial mass have a scatter of
$\sigma_{lnM200|N200}$ = 0.37 $\pm$ 0.05, while $\sigma_{lnM200|N200}$ = 0.77
$\pm$ 0.22 for the caustic mass and $\sigma_{lnM200|N200}$ = 0.34 $\pm$ 0.08
for the temperature based mass (abridged).
