The cheapest way I've found to start my garden plants and herbs is to re-use yogurt containers, eggshell cartons and the broken eggshells themselves. Using large plastic salad tubs as a mini greenhouse works great too! No more expensive jiffy pots and greenhouses for me.
For starting plants in the yogurt containers I wad up a small bit of paper towel and then fill with dirt. Plant the seed, water regularly and voila! It will germinate quickly and then you can plant it in the ground. Place dirt in an eggshell or bottom of eggshell carton and do the same. Works great!