Answer: The least expensive methods of obtaining flowers are growing annuals by planting seeds in the ground and by finding gardeners who are willing to share surplus divisions of perennials with you.
For the best success, you will first need to prepare the soil and then worry about plant selections suited to thrive in the location you have, meaning sunny or shady, moist or dry and so on. It is also important to run some basic soil tests and your County Extension can help you with that as well as interpreting the results and possibly suggesting plants known to do particularly well in your type of soil and location.
Most seeds for annual flowers would be planted around the last average frost date, bare root perennials would be planted in early spring and newly divided perennials can be planted in spring or fall. Spring blooming bulbs are planted in the fall as well.
You might wnat to take a look at a book or two about gardening to refresh your memory and to help you organize your project. One I particularly like is "Gardening for Dummies" by Michael MacCaskey, ISBN 1-56884-644-4, Dummy Press. You might also find the Dummy Series books on annuals or perennials helpful since you are particularly interested in flowers. Enjoy your new garden!
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