If you are not in a hurry and would prefer a less expensive method, the cost of seeding is reasonable. Of course, you don’t get something for nothing. To save money, you’ll have to wait longer for the grass seed to establish .
The preferred time for seeding cool-season grasses - kentucky bluegrass, perennial (not annual) ryegrass, tall & fine fescue - is the end of summer or early to mid fall. A lawn can be seeded in early spring but there is a greater chance for some weeds to grow as well.
Warm season grasses ( bermuda grass & zoysia grass) are, for the most part, propagated vegetatively. However, each grass species has its own set of possibilities. For example, zoysia grass can be seeded or plugged. bermuda grass can be seeded or plugged and can also grow from sprigs..
Warm-season grasses are best planted very late in the spring or early to mid summer. The extended period of warmer soil temperatures encourages rapid growth. Avoid late summer or fall seedings, as there is not usually not enough time for the grass to root well enough to make it through the winter.