Setting the bandwith limit on apt-get which is still what Ubuntu software Center and Synaptic use to get packages (I believe) is fairly simple. If you go into the /etc/apt/apt.conf.d directory you can add Acquire::http::Dl-Limit "70"; ("70" being the kb/s) in whichever parts of apt you choose.
You can download packages without installing them by using apt-get's -d option, used like this: sudo apt-get install -d packagename downloads the files for packagename. You can then run sudo apt-get install packagename offline to install the package. As far as putting restrictions, I don't know what you mean. You can make an account non-administrator so it prompts for a password of another user to install software.
Setting the bandwith limit on apt-get which is still what Ubuntu software Center and Synaptic use to get packages (I believe) is fairly simple. If you go into the /etc/apt/apt.conf.d directory you can add Acquire::http::Dl-Limit "70"; ("70" being the kb/s) in whichever parts of apt you choose.
You can download packages without installing them by using apt-get's -d option, used like this:
sudo apt-get install -d packagenamedownloads the files for packagename. You can then runsudo apt-get install packagenameoffline to install the package. As far as putting restrictions, I don't know what you mean. You can make an account non-administrator so it prompts for a password of another user to install software.