You can have the pleasure of picking the freshest berries every year for little or no cost* by growing your own. I'll explain how I developed the three rows of red raspberry you see below from just a few plants (that I found by the roadside).
Red Raspberries Plants
Berries are "invasive", ie. they spread by sending up suckers from their roots. However, I have been able to control them to my advantage. Once these new plants have developed their own roots, I transfer them to an open spot or a new bed. These first year plants and new canes on existing plants (see the tall canes in the above picture) do not bear fruit the first year. They have larger briar's than they will in subsequent years (but red raspberry canes are fairly gentle). They will grow tall enough to touch the ground where they take root. Once these young plants are established (in the following spring), I cut them loose and trim the long canes to the height of the supporting twine. The second year canes will be the most productive. Third year fruit will be smaller (or vines can be pruned off if desired, but definitely by the fourth year when they turn gray and die). I prune and compost during the dormant stage. New plants are also produced from seed, but will grow slowly. Unpicked overripe berries (because they hide so well) will drop off or birds will eat them and deposit the seeds (look in any bare protected areas). If you can learn to identify the seedlings, you can transfer them to your patch. My berries are ripening now. See below.
I also have a semi-wild patch of black raspberries ("black caps"). They are similar in shape to the red, but are smaller and are dark purple in color. The first year briar's are really nasty and the second year briar's are only slightly better. Berries grow in clusters with the center berry sometimes ripening first. Others ripen all at once (see below). Mine have now peaked, and will decrease and will be done soon.
Happy gardening - Mr. C.
*NOTE: If you would like some starter plants for your garden, please comment below or e-mail me at email@example.com.