Water purifier recommendations

Guys, maa daggara TDS ekkuva vundi like bore water around 1000 and municipal water 700. So thinking to buy water purifier but i heard these companies rob us with maintaince charges like for changing filters etc... We were using delivered mineral water can's but they aren't maintaining hygiene So which water purifier are u guys using & what are the average maintenance charges. Which water purifier do you recommend ? Thanks in advance