This is obviously fully going to be dependent on your unique situation, but getting a BSW significantly increases your odds of getting into a MSW. And there are several funded MSWs across the country (depending on if you're willing to move or not) as well as large government funding (NSERC, OGS - ontario, etc.) so you may not have to pay for the MSW at all. You run the risk of compromising BSW grades and thus your competitiveness for MSW funding if you try to work during the BSW, though, so that is of course an additional consideration. There is a lot to consider but I would recommend the BSW, even if just so you can register upon graduation and get higher paying jobs to work for a few years before your MSW.