I would recommend going with a $200.00 one to start with and see if you like using a serger. I bought a Viking 910 for $1000.00 and I would use it more if it worked, or I understood it better. Most complaints come from threading the machines. There is one that will "whoosh" and thread it for you, however, when the "whoosh" is gone you either need to pay for repairs or do it manually anyway. It just takes practice. I'm about ready to take mine and throw into the parking lot of the dealer!! If I had bought a less expensive one I could have bought 5 new machines by now.
The machine is going to make the same stitch, no matter how much you pay for it. So why pay more till you know you are going to love it!!!!
I do love making up pillowcases on mine. And I sew the seams on totes so they are good and strong. That is when it cooperates with me......................
Have fun and good luck!