Deborah they can charge 100% commission if they wish, does not mean anyone would hire them though. Commissions are negotaibale and you should ask what they charge, what they offer for that fee and negotiate. Discount fees can mean discount services. Speak with 2-3 agents to get a variety to help you decide.
There is no illegal commission. If you're selling and can't afford that then find another agent. If you're buying it doesn't matter to you since you aren't paying for it. This is not unheard of in some areas
Not only is it legal, but there are quite a few listings, especially land and commercial listings there for that amount - but I'm sure they vary. As stated below, it's always negotiable. If your property is land or commercial, try to find an agent in your area experienced in those types of sales.
It is true that all commissions are negotiable. If you don't like the percentage of commission that one agent requests than interview another agent (maybe from a different firm) and inquire what they charge as a commission.
Please, know that by Federal law (Sherman Anti-trust Act) that all commissions are negotiable to avoid price fixing.