job: what to do?

so i have been a stay at home mom for about a year now. we have recently moved into a new state (we live with family and plan to live with family for a while just to get more in savings to build or buy) and neither of us have jobs. we just arrived and we just put applications in. I put applications in Monday and Tuesday (yesterday). well one of the jobs I want to work for, called me back this morning wanting to schedule an interview for tomorrow because they have a spot they need to fill quickly. so here is the probelm: while I want this job I'm kind of caught off guard that this is happening this quick. I know that I don't actually have the job yet.. But if I am offered a position it makes me nervous because I want to do what is best for my family and make sure that the salary and benefits is what we want. so I'm nervous they might "low ball" me. But on the other hand I don't want to pass them up waiting on a "better offer" and then not getting anything. basically I'm scared to jump on the first thing that comes along but I don't want to pass it up either... thoughts? suggestions?