The most common type 3” Baseboard moulding

3” rounded trim is probably the most common type of baseboard molding you'll need. This type of trim used in a lot of new house. Basically, it's a piece that thickness from 1/2 inch to 7/8 inch and height 3 to 3 1/2 inches. The top of the trim has a gently rounded shape or subtly stepped shape, allowing it to taper into the wall.
Baseboard price will vary depending on the material of the trim. However, this is one of the best economic options you will find.
This baseboard trim style is best for a modern home. Because of its relatively short profile and simple shape, the simplicity makes it a great choice if you want the trim to recede into the background. This can be especially nice if you have elaborate crown molding or another feature you'd like to stand out.