Hi John,
Everything in one would be 40 odd DVDs worth but you can get the first DVD to install a complete OS (with some internet access being helpful thereafter as necessary). DVD 1-3 would give you some of the applications that are less used, but, to be honest, if you have adequate Internet access, you can use a Debian netinst CD. IF you have no internet access for one particular machine / need for a completely isolated network with no external connectivity, then there are two large .iso files you can create - one 16GB Stick or one Blu-Ray 25GB file - both of which can be written directly to a USB stick. Both of these large files require a Linux system and network access to a Debian mirror to generate but can be used independently thereafter. Note: the 16GB stick might require a larger 32GB USB - many USB sticks which are nominally 16GB are about 14.5GB capacity.
All the very best,
Andy C.