Optics is one of the areas which is a complete joke. The "traditional" Western players will sell you a pretty standard, small lens for $500, or do you a custom design at $5000/hr.
No one can afford it. It's a dead-end business. So the prices will continue to skyrocket, while the quality will continue to drop due to the total lack of ambition and innovation.
Meanwhile, a Chinese company will totally surprise you by doing you a free optical simulation when you just ask for an initial quote, in one day. For similar service (actually a 15-minute job, but no one likes to tell you this), you traditionally pay around $10000.
I have very good experience on sourcing lenses on Alibaba. Although, if you need a basic lens for a small sensor - something comparable to what's being used in average-quality HD CCTV or cheapish digital consumer cameras - don't expect to pay $50 on quantities. Expect around $2 in larger quantities, or around $3-4 in small batches.
We use the lenses in a low-resolution application, but low flare and high contrast are important for us, and several Chinese factories found from Alibaba provided high quality for that purpose.
And yes, you'll get real coated glass optics, in machined aluminium barrel, most properly engineered and optically simulated, at $2 from China. Maybe if you need to go much below $1, plastics will come into play.