There is an old adage in life and it basically runs that if you work for something you appreciate it far more!! That also applies to anything you buy,if you pay 450 bucks for a sling you give it all the attention in the world,if you get it for 10 bucks plus three free well???
My point if you breed out a 1000 cull 900 sell the rest for R250 ea,the buyers will appreciate them more.The risk of casual handling and escape will diminish.Lets be honest the Tarantula keeping fraternity is not big enough to handle the amounts been bred so a lot of these common species will end up by afterthoughts!!!!
What it boils down to is ethics not greed!Tarantulas are a hobby not a business for 99% of us and we should control it and manage the hobby.

So what do you suggest

I think the appreciation of your tarantula is more about availability than price. Obviously availability and price will be directly proportional.
I paid more for my first Chilean rose than most of my other T's, still I appreciate some of my other T's much more. Still love my little rosie though.
And the more of a specie there is, the more the prices will drop and the more people will be able to afford it, thus expanding our wonderful hobby.

as wynster says, cheaper helps encourage newbies to add more to the collection and our responibility to try encourage and introduce new ppl to the hobby which will help with the slings!

Is cheaper encouraging the kind of people you want in the hobby?? Do we need a whole heap of T keepers because its cheap and an outlet for cheap slings or genuinely interested people prepared to pay their dues?
Lets be honest what is a hundred bucks for something that could potentially give you 30 years of pleasure?
It cost a lot more for a trip and movie ticket for two hours of entertainment.

It is impossible to control what type of people comes in to our hobby. Do you think everybody that can afford a R450 tarantula is as passionate as me or you?