I, too, bought a used one on CL. Paid about $50 I think for a Brother 4-thread machine. Wasn't sure how much I'd really use it so didn't want to invest big bucks. She lost the manual and I actually paid $20 to get a copy of one. Not a great copy and the threading diagram was the pits. Had it serviced at my regular dealer for a reasonable fee. Then found out that a not quite local to me LQS was offering classes on sergers. The 3-4 classes were another $50 or thereabouts. VERY good instructor. Well worth my time, $$ and gas. All that said, I think I've used it 1 or 2 times since then. Overall I'm happy with the route that I took for this purchase and the total $$ spent. It's there if I need/want it for something without having spent really big bucks. And the books/instructions I got in the class are all still there for reference. The best tip for threading from that class...tie the new thread to the old and just pull each one through...at least then you know you have it at least threaded correctly. Another big tip - keep a log of the various adjustments you make for different techniques. Write down your baseline settings; then when you do a rolled edge, for example, write down those settings. This way, when you want to go back to normal serged edge, you know your settings and reduces the frustration factor.