Major e-commerce platforms, local gold and jewelry markets, and offline jewelry stores.

1. Search for 18k gold discount on major e-commerce platforms, compare the prices of different merchants, and choose the one with lower price.

2. Visit the local gold jewelry market or jewelry wholesale market, compare the price and quality, and choose the higher 18k gold discount.

3. The jewelry store and gold jewelry store under the line ask about the specific price and quality, compare the prices and services of different businesses, and choose the appropriate 18k gold discount.