Here is one that sold on eBay for about that price:
http://cgi.ebay.com/Baby-Lock-eclips...item2a0e82863c
The hardest thing about a serger (in my opinion, anyway) is threading. Air-threading is a really nice feature to have, and I don't know if this model has it.
I will point out that this is a 4-thread serger. A 5-thread serger is nice for hemming t-shirt type material and decorative stitching (which would apply to flannel blankets).
If you can't figure out the serger by yourself, there may be a serger class available in your area where they will help you learn how to use your serger. I have seen them advertised in shops that sell fabric. It would be really helpful to have somebody to call if you get stuck while learning. Until you are familiar with how a serger works, it can seem a little mysterious. However, these days there are so many Youtube tutorials (not to mention people you can ask here on this board) you can probably work it out for yourself just fine.