Viking software alternative

I want to purchase a used viking designer se le...the problem is I cannot afford the viking software. It does not come with the machine and my understanding is that they can only be registered once anyway. What exactly do I need to run it and do designs that I draw myself. Do I need a basic Viking program ? (4d way out of my $ range). Can I just use Embird or Sew what pro? Please someone help me and tell me what I will need?