To get aftermarket stock prices, you can use the following resources:

1. Brokerage Platforms: Most online brokerages like TD Ameritrade, E*TRADE, and Charles Schwab offer real-time aftermarket quotes to their clients.

2. Financial News Websites: Websites such as CNBC, Bloomberg, and Yahoo Finance provide aftermarket stock prices, though they might have a slight delay.

3. Stock Market Apps: Apps like Robinhood, Webull, and Fidelity have mobile platforms where you can view real-time aftermarket prices.

4. Market Data Services: Services like TradingView offer advanced charting tools with aftermarket price data.

Always ensure that the platform you choose provides the most up-to-date information, as aftermarket trading can be more volatile and less liquid than regular trading hours.

Here are some of the best brokerage platforms for accessing aftermarket stock prices:

1. TD Ameritrade: Offers comprehensive tools and real-time data, including aftermarket quotes through their thinkorswim platform.

2. E*TRADE: Provides robust trading platforms with access to aftermarket data and advanced charting tools.

3. Charles Schwab: Known for excellent customer service and a reliable platform, Schwab offers real-time aftermarket prices.

4. Fidelity: Offers a user-friendly platform with access to aftermarket trading and real-time data.

5. Interactive Brokers: Known for low fees and extensive market access, including detailed aftermarket data.

6. Webull: A mobile-first platform that offers free real-time aftermarket quotes and extended hours trading.

These platforms provide reliable access to aftermarket prices and are well-regarded for their comprehensive tools and features.