You can definitely grow your own lawn from seed. The cost of grass seed is a lot less than sod, but then take into consideration the fact that growing from seed requires a LOT more effort than sod. The ground must first be graded and rolled, seed must be applied evenly to the entire area, and the watering regimen is pretty involved for several weeks. You would also need a way to keep everything off the seeded area for a few weeks, so the germinating seed isn't disturbed.
Then, once the grass is starting to grow, you will go back and overseed the areas where the seed wasn't distributed, resulting in bare spots. And the process repeats itself for those particular spots.
Now, consider that you can walk into Home Depot or Lowe's, give the garden center the square footage of your yard, and they will deliver and install your sod (unless you want to roll it out yourself). After just a few days, your lawn is established and ready to go.
While grass seed may be cheaper, the value of your time and energy adds up fast. If you have plenty of both, give seed a shot! Otherwise, sod becomes a pretty good bargain.
It depends too, on soil type, sun vs shade, drainage, alot of questions to answer before you even start planting seed. Where you live, climate, etc.. Also play in the decision. You should be able to talk to your lawn and garden center to answer these questions and decide on what's best.
We are fast approaching grass seed season. If the lawn does not require much prep, you can sow it any time, even on the snow. Do not wait til July and august, think springtime and have fun. Do not oversees and allow it to get quite long and then set the mower high with a freshly sharpened blade. Fertilize with a starter fertilizer and do not worry about weed and then apply weed and feed in the dew of the morning on a day with no rain and then you are off to a beautiful lawn.