The GPL does allow any company to take GPL'ed code and make a commercial product derived from it. Note that I said commercial product, not proprietary. To respect the license, they would have to distribute the source code of their derived products along with any binary they sell, and they would have to use the GPL again. So yeah, they could try to sell it for a hundred dollars, but the first buyers could then redistribute freely under the GPL. This removes the incentive of over-charging.
As for a company taking GPL code and building a web interfcae out of it and charging $1000 for each access, I guess this is possible since they aren't redistributing code, but rather providing a service. But if the overhead of building their web interface is not worth $1000 (or even $1) a shot per clients to use, the market will tell them so. A competitor will do the same for less. Hopes this helps. I am not a lawyer. Peter
