• how tall do you need your posts?
• shelf dimensions (width x length)?
• how important is condition (cosmetically)?

All the options: shelves, posts, nuts & bolts, bracing (corner gussetss or cross braces)

Most common post heights: 4, 5, 6, 7, 8, 10, 12 feet
Most common shelf sizes: 12" x 36", 12" x 48", 18" x 36", 18" x 48", 24" x 36", 24" x 48"