I think you need to be careful here. You mentioned on another thread that you have been offered a PhD position. I can't see how you will be able to do a Research Assistant role and do a PhD. Alot of PhD students will do a bit of teaching to supplement their incomes, but this is often limited to, say, 6 hours per week inclusive of prep time. Other than that, if money is a worry to you, your only other option is to do some quiet moonlighting, but there could be a heavy price to pay for that.