Another option is to use
Pre-requistes: A friend's system with Internet connection. apt-offline installed in both your systems.
The Offline installation is achieved in 3 simple steps.
Generate a signature file on the Disconnected Debian box at home
apt-offline set /tmp/apt-offline.sig
The above command will generate all information required from apt about updating its database.
Download data based on the signature file generated earlier
apt-offline get C:\apt-offline.sig --threads 5
The above command will download data as mentioned in the signature file. To speed up downloads (that can be from multiple apt repositories), in this example we spawn 5 download threads.
Once completed, you could just copy the data (an archive file, if you used the --bundle option) back to the removable medium and copy it back onto your offline host.
Once you're back upon the home Debian machine, you feed the data from the removable medium to apt-offline:
apt-offline install /media/USB/apt-offline.zip
This will update the APT database on your disconnected machine seamlessly.
Apt-offline can be even be used in Windows systems. In my opinion,
apt-offline is the best option for Offline installation.