Long Arm University lists used longarm setups for sale. I bought my Q'nique from a seller on that list.
I did that because I did not want to invest heavily when I was not sure I would like longarming my quilts. I got a very nice setup that ran well (she sent me a video) for around $3000. I had to travel a ways to get it but that was a fun road trip with my daughter.
I will probably upgrade at some point but I have had this machine for several years and it has, knock on wood, been a dependable, low cost machine that let me get oriented in longarming. No regrets....and even if it had not gone well, I had not invested a small fortune and could afford the loss.