The cheapest SMD (no THT soldering) switch
LCSC offers the SHOU HAN MSK12CO2-SZ microswitch for about 0,023€/pc @ 1kpc. One of the disadvantages of this switch is that even though it is a pure SMD (no through soldering required), it is shipping as bulk in a bag and not as tape. Therefore, it is not suitable for all commercial assembly lines and needs to be assembled manually.
But at least it is cheap – that is, if you buy enough stuff to justify the high LCSC shipping costs.
The KiCAD footprint for this switch is Button_Switch_SMD:SW_SPDT_PCM12. Even though it’s a different switch than the C&K PCM12, it’s mostly compatible footprint-wise – even though the drill sizes are very slightly off, the footprint works well.
This switch is likely rated to DC12V, 50mA (listed as such on the LCSC website). However, from the datasheet, the exact rating is unclear, it mostly covers the test conditions
The cheapest tape&reel SMD switch
If you are looking for an alternative suitable for automated assembly, take a look at the SK-3296S-01-L1 which comes as a taped reel. It is almost 35% more expensive but given that it’s still just 0,031€/pc @1kpc and given that you’re likely not a chinese electronics designer in extreme mass manufacturing, the price is hardly worth thinking about.
It is exactly compatible footprint-wise with the C&K PCM12, so the KiCAD Button_Switch_SMD:SW_SPDT_PCM12 works even better.
This switch is rated at DC12V, 50mA.
The cheapest 1 Ampere rated switch
This is the MK-13C03-G010 which is rated at 6V 1A or 12V 0.5A. This type of current rating with voltage is related to arcing when breaking the contact.
It is priced around 0,11€/pc @1kpc.
This one is compatible with the C&K PCM13 (but rated at higher current), so use the Button_Switch_SMD:SW_SPDT_PCM13