Compost.
Ideal for soil growers, and you can easily make your own with organic matter that you would generally throw away.
Not the optimal nute regime by any means, but it can save you some money.
IMHO - A quart for $20 is well worth it. Buy 2 grams less weed and pick up the plant food!
That one quart bottle will take ages to run out.
Most nutes are applied as a few ml to gallons of water. When you start out, you should be using 1/4 strength nutes, so just picture how economical it is!
The one bottle will last you through your grow, depending on how many plants you plan to grow!