what is said special soap?

i just use walmart brand salen solution. im too cheap to fork out $5 a bottle when the walmart brand is like $1.14

so is said soap really effective or no? i noticed that after a while (3 weeks or so) my contacts would start to get hard and more irretating so i would have to switch them. im really leaning towards daily disposables because i guess they are more "cleaner" than normal contacts since you replace them daily. sorry for all the questions i just want to be thorough h: