We have an under sink water filter. These things cost about fifty bucks for just the canister. You can't completely empty them. We use our moho for about 3-4 weeks out of the year. Cant we somehow use...
It really depends on what you want to filter. You can remove particles, chlorine, bacteria, etc. After you do the particles, the rest is more expensive. We have an undersink EverPur that handles chlorine and some particles. The elements are $38 from efilters.com. The element as used needs replacing yearly. We also have a whole house outside filter from HD that will use either a particle or carbon element. This is changed every 6 months. Good water.