My 10-year-old MacBook got dropped from Skype support some time last year and I won't get it back till I can find something that will run a more up-to-date OS.

Face-Time has been suggested as an alternative but requires an Apple ID. I must have had one once, but "forgotten password" only gets me to an endless loop.

My partner, currently in New Zealand, accidentally discovered that Facebook Messenger or Chat facility allows computer-to-computer talk for free (phone symbol on the blue bar atop Personal Message panel). With video switched off, conversation was possible, if occasionally a bit distorted, even on my (recently) 1Mb BT Broadband "service".
Ross