To make a stylish and trendy DIY vase in a budget-friendly way using an old detergent bottle, start by rinsing and cleaning all the detergent off the bottle.
It can be as tall or short as you like, but ensure it's sturdy and secure it with tape. Use the moist gypsum plaster to cover the bottle, including the newly structured neck.
Sand off the rough edges and repeat the gypsum plaster step if necessary. Mix the drywall putty with water, then apply a layer to smooth out the vase's surface.
Let the plaster dry and sand again if necessary. Standard wall paint works due to the materials used. If you want to create a high gloss, you can also varnish your new vase.