Just wanted to throw out a couple more ideas. . .
I have 5 pound ankleweights with the removable 1 pound packets. If I need to use a 6 lb. dumbbell, I just hold the little packet in my hand along with a 5 lb. dumbbell.
Adjustable dumbbells are cheaper than buying them individually and take up less room. I have adjustable dumbbells from 5-50 lbs that go up in 2.5-5 lb. increments so I have 5, 7.5, 10, 15, 17.5, 20, 25, 27.5, 30, 35, etc. up to 50 pounds. Using the platemates on them I can also get 22.5, 32.5, 42.5 and 52.5.
Sue