You can limit the number of buy/sell transactions per player, per item, and per period.
The system supports both numeric cooldowns (in seconds) and periods (DAILY, WEEKLY, MONTHLY, YEARLY, FOREVER).

limit:
  buy: 100           # Max items a player can buy per period/cooldown
  sell: 50           # Max items a player can sell per period/cooldown
  cooldown: 3600     # Cooldown in seconds (here: 1 hour)

Or with a period:

limit:
  buy: 1000
  sell: 1000
  cooldown: DAILY    # Reset every day at midnight

Available periods:

• DAILY (reset every day at midnight)
• WEEKLY (reset every Monday at midnight)
• MONTHLY (reset every 1st of the month)
• YEARLY (reset every January 1st)
• FOREVER (never resets)

• The plugin tracks transactions per player, per shop, per item, and per type (buy/sell).
• When the limit is reached, the player cannot buy/sell more until the cooldown/period resets.
• The plugin displays a message with the remaining time or amount.
• Limits are stored in the database and cleaned up automatically.

• /resetlimits <player> [shopID] [itemID]
  Reset all limits for a player, or for a specific item.

• You can use different limits for each item.
• If you set cooldown to a number, it is interpreted as seconds.
• If you set cooldown to a string (DAILY, WEEKLY, ...), it uses the corresponding period.
• If you omit limit.buy or limit.sell, there is no limit for that action.

items:
  diamond:
    typeDynaShop: DYNAMIC
    buyPrice: 1000
    limit:
      buy: 10
      sell: 5
      cooldown: DAILY

  gold:
    typeDynaShop: DYNAMIC
    buyPrice: 500
    limit:
      buy: 100
      sell: 100
      cooldown: 3600 # 1 hour

Note:
Limits are enforced even if the server restarts.
You can monitor and clean up old transaction data automatically (see plugin logs for details).