How to Sell My Stock Certificate Online

Open an account with a discount online broker if you don't already have one. You can use a full-service broker or the company's transfer agent if they offer online services. However, you will probably pay higher brokerage commissions or transaction fees than discount brokers charge.
Fill out the transfer of ownership form on the back of each stock certificate. Call the customer service number for your broker to make sure you enter their name and other information as required. If you don't already have the broker's mailing address, this is a good time to ask for that as well.
Send the stock certificates to the broker by certified mail with the U.S. Postal Service. Because stock certificates may be of considerable value, they should be insured when you mail them.
Wait a few days to allow time for delivery and processing of your stock certificates. You'll see them credited to your account online. All you have to do then is place a sell order with the broker.
Keep complete records of the transaction. At tax time you'll need them to report any capital gains or losses.

How to Buy Sprint Stock

Find a broker. These are companies like E*trade, Ameritrade, and others that allow you to buy and sell stock. There are two major types of brokers. Full service brokers provide many investor support services, such as research on companies and advice on stocks. Discount brokers charge less of a commission for trades, and some offer online research services, but will not have as many investor services as full service firms.
Decide how much money you want to invest in Sprint stock.
Find the current price of Sprint stock. The full company name is 'Sprint Nextel Corporation', and the stock symbol is: NYSE:S. Online brokers will have a search function on their websites, but you can also find stock prices without a broker through Google Finance or similar personal finance websites. (See Resource 1.)
Divide the amount of money you want to invest by the current price of Sprint stock to determine how many shares you should buy.
Place the order with your broker. Online brokers will have account management options that allow you to buy stock through their websites. Some online brokers will also have you register a bank account or debit card to cover payments for stock; payment will either be taken out automatically as you buy stock, or you will need to send a payment through their websites after purchasing. Other online brokers, such as Charles Schwab, allow you to deposit money into a brokerage account and use those funds to purchase stock.