Undesirable jobs for human migrants in space opera

I create space opera world, where XX Earth was contacted by galactic community. Because tech difference levels between end of XX century Earth and spacefaring civilization many humans try emigrating into more developed worlds for better life.

But I have little problems - what tasks can be given to human immigrants in "average space opera" setting (think about something like Star Wars or Mass Effect as rough guideline). They don't have enough tech and science education, don't have some unique skills (or more correctly have, but it different "branch" of immigration)?

So what low-payed jobs can be filled by humans in such setting?