I will make two suggestions. First, save your money. A Nakiri priced at $40 is very likely going to be poor quality. You will have spent your money and when you're finally tired of the poor grind, dull/chipped edge, split handle or whatever else might go wrong with it, you will either have to start over or simply go without. Second, call chefknivestogo. The owner took a fair amount of time to talk to me and help educate me about Nakiris when I was looking for one. He was very knowledgeable in general and certainly knows a lot about what he carries. He is not like an employee who has no interest in kitchen cutlery and is just looking for a paycheck.
I think you can get something relatively decent for under $100, but you're going to have to be patient and work a little bit for it. Still, it will be worth it in the end.