I bought one used from Craigslist last year. Paid $40-50??? Can't remember exactly. Had it serviced at my normal repair shop for $75-100. It did not come with a manual. I was able to purchase one online but it was a crappy copy. I couldn't figure out the threading. A not so LQS was offering serger classes for $10/session. That instructor was excellent. Took 2-3 of those and can now at least follow what I have been taught. Don't really use it for much so, like you, didn't want to spend big $$. I'm happy with my decision and went into the process not uninformed as to what I was looking at $$-wise for cost/tuneup and the classes were far less than I anticipated spending. I would suggest looking online at different manufacturers/models to see what might be what you would like. I'd go for at least a 4 thread as I think you can get nicer edges with the additional thread. Then keep your eyes open on CL. They are out there frequently and cheaply enough that you should be able to find one fairly quickly/easily. Just my opinion.