For basic Davis you need either the Vue or VP2 station (ISS and console) and you can also use the Vue console with the VP2 ISS or visa versa. There is a wired and wireless version (wired from ISS to console or wireless from ISS to console). If you want to connect to computer/internet then you also need the datalogger which is the hardware/wire that connects the console to the computer/router and stores the data for when the computer/router is not connected or running - Davis Weatherlink in either USB, Serial or IP versions. But third party dataloggers/computer connections are available. Davis Weatherlink datalogger package comes with their Weatherlink software to get you started. Many/most opt for third party software though, such as Cumulus and others. Cumulus now comes in CumulusMX version which is Windows, Mac, Raspberry Pi, etc. compatible.
A search will get you several good US vendors that sell below Davis' list prices. Make sure you ask for their best price as that is not the one usually listed on their site. Most users have their own preferences.
Many other options available to use the Davis stations. Once you have a general idea what you want/want to do there will be lots of responses to your questions here.
Enjoy,
Paul