Help please! I have an opportunity to purchase a Pfaff 7570, a Bernina Artista 180, and a Bernina 2000 D4E serger. It's from an estate sale and I have no idea what to offer. They have not asked any amount, so help me out here. Does anyone have either of these machines or know what they might be worth. I'm assuming they are in good shape and working order. Thanks in advance. I may get killed for buying all these, but hey, life's short anyhow!