Most domestic vehicles depending on trim and geographical area come with a block heater from the factory. When I go to northern Ontario hotels don't offer me the option to get a smoking/non smoking room, they ask if I want a cord to plug in my cars block heater.
If you park in an area that is COLD, as mentioned above, it's best to plug the vehicle in right away. Most block heaters are around 400watts and they keep the engine oil from congealing.
Engine blocks have freeze plugs. Once the coolant freezes these plugs will expand when the coolant freezes and push out of the block, in which case the block is saved, but you cannot drive it. Earlier block heaters meant lighting a fire under the oil pan.
You can also check a local salvage yard. Someone I know bought one there for $5 brand new for his truck. My GT came with a block heater from the factory. I normally take my Durango up north on trips and its block heater is used nearly each night I park.
'11 Ram SXT 4x4 quad cab - 5.7L V8; 128,200kms
'09 Malibu 2Lt 3.6L - 140,000kms purchased 1 March 2019
'06 Pontiac G6 GT - 3.5L V6; 162,000kms (rear ended 15 Feb 2019, and given totalled title by insurance)