The easiest highly successful method I know of for hydro growers requires about $15 in supplies.
a 5 gallon bucket, aquarium air pump and air stone, a styrofoam dinner plate.
Fill the bucket 80% with tap water and run the hose and air stone to the bottom of the bucket.
Poke holes in the styrofoam plate to accept the cuttings. You want them to fit just slightly snug.
After you fill the plate with cuttings simply place on top of the water and you are done. No rooting hormones or humidity dome needed.