you can probably get a Radeon 32MB or a Radeon LE (or even a radeon Ultra) wich will be better than a GF2 MX
or a Kyro 2 32MB
those should be around 75 bucks
MUCH better choices
you don't really need 64MB so don't get stuck on that spec.
only MX I could ever recommend would be the 400...
according to many sites the GF3 MX will be expensive as hell (though some say the exact opposite)
if you can afford it, it would be a good choice though