You can make a home made sea salt spray that you spray on 2 hours before you wash, Not table salt, that is different. Sea salt can be bought at the grocery store, bulk food stores and even aquarium stores sell it for their sea salt water tanks. Add a couple of tablespoons of the sea salt to 5 cups of water & spray on hair, not scalp. Try not to leave it on more than 2 hours because it can start to dry out your hair. This recipe will help with your journey.
Shampoos out there are not really mean for dreads because of residue build up. If you don't have the money to purchase any right now, then use the baking soda wash, apple cider vinegar rinse. I used it for an entire year. Many people have hard water, so many shampoos and even dread soaps, like Dr.Bronners will not rinse out well for them. If you have soft water, you can use just about any dread shampoo or dread bar, but if you have hard water, then go with the Dreadlock Shampoo items which are made specifically for dreads and hard water.
Oh yeah, most regular shampoos will cause knots to slip out also, so beware.