When a founder tells you "the salary is low, but you get equity" he is screwing you.

If you take a market salary, and see equity as what it is (a lottery ticket that might, maybe get you a few tens of grands) then it's fine.

Definitely the former, unless you feel that only co-founders deserve market pay and equity that pays out at >$0. In many cases, employees even lose money because they have to exercise options with no insight into if they'll ever be worth a dime.