It depends upon what model of Huskylock it is - my first serger was a used Huskylock and it was INSANE to thread. I mean real tears! Gosh, that was the most frustrating bit of machinery I've ever touched. Once you got it sewing, it was great, but getting it threaded - Lord, have mercy!
Then I got a used Babylock 400 serger and I liked that all right, but it was a bear to thread and it didn't do some of the things I wanted it to do.
So I bought the very cheap Brother 1034D on walmart.com - less than $200 and I use it all the time. It's so easy to thread, I can almost do it with my eyes closed. Changing to a narrow rolled hem takes seconds. It's quite a bit noisier than some of the very expensive sergers, but I'm not using it for hours at a time, so I just put up with it.
Whatever you buy, make sure that it will be easy to thread. It takes the fun out of it when you have to spend an hour threading and re-threading before you can even use the machine.
This being a used machine, it may be elderly enough that it doesn't even have a differential feed. There are a lot of normal sewing situations which require that differential, so make sure it has that.
Good luck and have fun!