underfire, these sorts of webcams (Actually IP Cameras are what we're talking about in this scenario, but I'll just be using the term Webcam here) are actually very low bandwidth, generally updating only every few seconds and don't need to be high quality either, heck, having them update once every 15-30 seconds is more than adequate, the size of the image only needs to be about 150-200kb so uploading one of those every 15-30seconds requires a very tiny amount of bandwidth. Generally costing between $100 to $200 for an all inclusive IP Camera that is ready to be hooked up to a network, looked after by whomever looks after the Airport but they don't require a lot of maintenance, generally the most required is a reboot once in a while and replacement is of course relatively cheap, just need to replace the actual unit.
You can also buy some pretty good set ups for more like $1700 but these are fully controllable (Pan, Tilt, Zoom), have Wifi and 3g built in along with a Solar Panel and Internal Battery to run it as well. Of course these would be idea as they'd require very little effort to get up and running in terms of on-site installation.
Some quick numbers, say you take an image every 30 seconds, about 150kb each, running from Sunrise to Sunset that would amount to usage of about 230mb a day or about 7gb a month, which is not a great deal so cost of Bandwidth per year would be very limited, perhaps $40-50 a month?
I lived in Vanuatu for a few years and they had some great webcams setup on a hill over looking Port Vila which were absolutely brilliant (Sometimes even essential) to get an idea of what the weather is actually doing and I know a great deal of GA Pilots would use them around Australia if given the ability, especially with access to them inflight through various devices readily available now.
I also don't see what you're point is about Pilots not being allowed to acces or use cameras mounted on Aircraft? What exactly are you talking about with this point?