Your search for "effervescent tablet" revealed the following:

Sale price £77.43 Regular price £90.00 Sale
Sale price £19.99 Regular price £30.00 Sale
Sale price £31.40 Regular price £50.00 Sale
Sale price £97.94 Regular price £130.00 Sale
On Sale from £39.45 Regular price £50.00 Sale
Sale price £29.95 Regular price £40.00 Sale
On Sale from £33.53 Regular price £40.00 Sale
On Sale from £61.95 Regular price £90.00 Sale