Based on the thousands of offers from hundreds of start-ups that I've seen DeveloperAuction, that is definitely a little bit on the low end for a "late stage" startup (Series B+?) company, but you're not horribly far off.
You could probably get $125K-$130K elsewhere, maybe even more, and potentially with a signing bonus as well.
$100-$115K is a typical salary at a seed stage company which would offer a significant equity stake