There are many hardware phones to choose between, but it is important to pay attention in order not to buy a phone where proper SIP telephony is restricted. Unfortunately many of the so called SIP phones sold in for example Sweden are restricted so it is only possible to call traditional phone numbers not containing letters or special characters. But if you know which phones work well, and are not restricted in any way you can get very good phones at a low price.
When the hardware phone has been bought, it needs to be configured for the SIP provider that is used. This is described for each phone model.