Your search for "effervescent tablet" revealed the following:

Sale price £16.99 Regular price £20.00 Sale
Sale price £57.95 Regular price £70.00 Sale
Sale price £58.12 Regular price £70.00 Sale
Sale price £26.87 Regular price £30.00 Sale
Sale price £32.49 Regular price £40.00 Sale
Sale price £32.49 Regular price £40.00 Sale
Sale price £16.99 Regular price £22.00 Sale
Sale price £13.99 Regular price £20.00 Sale