So whats the craic with tennis?

Hey looking to start playing tennis and was wondering what's the best options.

I'm on the North side and I know there's a few things about. Are there places I can play without being a member or will I needed to join a club? Anyone had experiences with any trainers?

At the moment I'm thinking Westwood in Clontarf is the best option, not too far, they have courts and trainers, and training sessions with groups so might meet someone to play with regularly. But are there cheaper options?

Also I see people online hitting balls against training walls, is there anything like this in Dublin? Haven't managed to find any.

Any thoughts? Thanks