Ummm.... guys?
I know the OP has given the budget at $100, but is there any reason to actually assume that's real?
OP- your mother doesn't sound like she was enthusiastic about this. I'm going to make a bold assumption that she is not a "knife knut" in which case it may not even occur to her that a knife could cost as much as $100. Many people outside our community would laugh as us for spending more than $30-40 on a knife, and I'd double down on that if it's not something they are enthusiastic about, which seems to be the case here.
I guess ultimately my question is, OP, why do you imagine that your budget is $100? The folks here tend to be incredibly helpful, but the information we provide can only be useful to you if you give us the basic facts.
We don't know your intended use, what size you are looking for, or what the actual budget is.