I had a quick look to see if this had been mentioned but couldn't find anything, please delete if I have duplicated another post.
Tesco are selling their own make of bubble bath spa for £12.49. This is a long blue mat which adheres to the bath by suction cups and air is pumped through it to cause the spa effect.
(I have looked on the Tesco site and can't see it there, they only have a BaByliss one at £74.99.)
In the store I was in, they had them situated beside the bubble baths and shampoo etc. The assistant said most stores should have them.
I bought one, not expecting much but I was surprised how powerful it was. It has 3 speed settings and 3 timer settings and is operated by remote control. It also comes with it's own RCD adapter plug.
I don't think I'd have paid £50 for it but it's definately worth £12.49. Sorry, no links to show you the model.