I recently purchased the PE-770 myself, and I was wondering about the 90# bobbin thread as well. I wanted to stock up as well on threads and such, and I just purchased a set of Polystar thread, has 63 colors for $99 online from mrvacandmrssew.com. When I was at my local Brother dealer before purchasing my 770; the gal told me that the thread ran about $5.99 per spool; so in my opinion, this was a pretty good deal. And from what I've been told, you do need stabilizer on all embroidery, the type depends on what material you are embroidering on. Sorry if I'm incorrect on any of this, as I am totally new to it. There are a couple of threads on the board that may have more information--Embroidery Machine Lovers (which has over 900 posts and is kinda hard to follow) and a new one Embroidery Machine Lovers July 2012.