When purchasing either a Cisco router or switch please ensure that either the router or switch comes complete with preferably the latest appropriate Cisco IOS software.
Should you purchase either a Cisco router or switch without the appropriate Cisco IOS software it may well render the device useless as you may not be able to download for free from Cisco the relevant Cisco IOS software.
To download a Cisco IOS goto Cisco.com official site then "Support" then "Download Software" then for example "Switches Software" ignoring the "padlock" icon.
After purchasing either the router or switch please ensure that you backup the devices Cisco IOS software.
Should you be required to also down load a TFTP server then try SolarWinds.com web site for free.
I once purchased a Cisco router not knowing it did not come complete with a Cisco IOS installed and todate the device still remains as a dust collector!!!!