With my first we bought the big blue jugs. My husband always kept up on them so it was never really a hassle to me...it was kind of nice cuz the dispenser has hot or cold water so I could just put a little of the hot and then some cold and have a bottle instantly instead of having to heat it up. I'm not sure about the best brand of sink ones tho, sorry!
I just bought the jugs of water..they're only like a dollar per jug but if you don't wanna buy the jugs and can't hook a purifier up to your sink then they have the water purifier pitchers! Just fill with water and it purifies it!
I bought a kettle and filled it every morning and let it boil. All I would have to do is pour it in the bottle add the formula and shake. It worked great cause I always had boiled water on Hand. My mom gave me the idea, just make sure the kettle is cleaned and u boil water in it first then through it out and reboil water in it again to make sure the kettle is cleaned.
I bought a brita pitcher. ..I think I paid 25 but its convenient yu just keep filling it