I also saw it happen at a startup that initially relied heavily on outsourcing, after a couple years they started bringing some of the best Indian guys in-house.
It's not cheap, but it is certainly not that expensive, as those fees will usually be less than 1 month's salary of the hired developer.
In my opinion, timing constraints and uncertainty end up being a bigger deterrent: you can only apply on April, the visa start the following October and it takes a while to know whether the applicant was selected.
It required a lot of documentation, but else the process was fast and pretty painless.
Does anybody with a lot of experience with Visas have a better price quote?
We have other E-3 employees as well.
http://www.puppetlabs.com/company/jobs/
Ultimately you need to make a judgement call when hiring. Is the position important enough to justify the cost of the visa application and processing?
I'd argue that at an early stage for a startup, just about every position is that important. The right person matters a lot.
The bigger problem might be the time it takes to get all these applications done.
The USCIS doesn't exactly operate at startup pace... :)