Salad greens such as mesclun or fancy lettuce can be up to $5 a bag. This can add up to over $250 a year if you buy a pack each week. But for just a small up front cost, even the non-gardners among us can produce an ongoing supply of fresh greens for salads and sandwiches.
Most kitchens have at least one sunny window sill. Somewhere that gets morning sun but not the hot afternoon sun is best.
Purchase a rectangular planter box that will fit on the window sill. Fill it to about 2-3cm (1'') below the rim with potting mix. Mix together about 1 cup seed raising mix with 1/2 teaspoon "salad green" seed mix (available at most garden centers).
Spread the mix containing the seeds out on top of the potting mix.
Keep watered, and within a few weeks you will have fresh clean salad greens right on your windowsill.
After a few weeks the salad will need to be replanted. Have two planter boxes on the go so that when one needs replenishing you can still pick from the other one.