Landscape plan
Draw the block. Beds, paths, paving, decks, retaining walls, steps and the shed you have to plan around. Then plant it, with everything drawn at the size it finishes at, not the size it is in the pot. You get the materials list, the plant list and a plan you can print.
A raised bed is sleepers filled with soil. In the ground is dug and edged, and a lot cheaper.
Not many blocks are a neat rectangle. Pick the closest, then tick Edit boundary above the plan and drag the corners until it matches your title. Tap a plus sign on any edge to add a corner.
A garden is not a spreadsheet and a landscape is not a set of drawings until somebody digs it. Here is exactly what this thing believes, so you know when to overrule it.
The short version. Quantities are for planning, not for setting out. Plant sizes are what they finish at in decent soil with enough water. When in doubt, leave more room and buy ten percent more of everything.