You can plan for your spring garden in the fall and save money. Take your flowers that are dying off in the fall months and gather the seeds. Let these seeds sit on a paper towel or newspaper for about a month to dry out. After the seeds are completly dry, you can put them in a air proof container or baggie for the next spring planting.
Cutting your plants and hanging them upside down over a large piece of paper will allow you to gather seeds without having to pick out every tiny seed that is on a certain flower.
Taking seeds from watermelons or other melons is easy - scoop them out and place them on a paper towel. As the seeds dry you can pick off the melon pieces with your fingers without the goo.
Growing your own plants from seed that you have saved yourself is rewarding so go on, have a go.