Plumber is not Plumber
Some charge more than a Surgeon and no Insurance on a Plumber..
1: Some of the filtered water systems have a fitting that fits over the end of ya cold water tap / spout eic....
Can not say how good they might be or NOT..
Have seen some with a T / flick switch / fitting that will allow you run another hose off to another bench mount system.. Could suit a coffee machine..
Would suggest a search of e-bay and other household / kitchen places.. *Some of the water filter places may also be worth a try..
Some of these are DIY and thus big savings and easy to pull down / dismount and take with you *;)