The name Issachar consists of two parts. The first part of the name is disputed. NOBSE suggests a root in the word (ish 83a) meaning man in the sense of a function (man of such and such). This word is written with an aleph, which does not occur in the name. Jones sees more in the word (yesh 921), which means existence, there is, are. Note that both words are written with a while the first name segment is contains a .
But at least there is agreement about the second part of the name. It comes from the verb (sakar 2264.1) hire, wages.