Update ch01.asciidoc

ch01.asciidoc

@@ -129,7 +129,7 @@ When Alice runs Bluewallet for the first time, she chooses the option to create
 .The Bluewallet Mobile Wallet
 image::images/bw_0101.png["BluewalletWelcome"]
 
-((("addresses", "bitcoin wallet quick start example")))((("QR codes", "bitcoin wallet quick start example")))((("addresses", see="also keys and addresses"))) The main wallet view displays the bitcoin amount, transaction history, as well as _Receive_ and _Send_ buttons. 
+((("addresses", "bitcoin wallet quick start example")))((("QR codes", "bitcoin wallet quick start example")))((("addresses", see="also keys and addresses"))) The main wallet view displays the bitcoin amount, transaction history, and _Receive_ and _Send_ buttons. In addition, many wallets feature the ability to purchase Bitcoin directly through an exchange or similar service where you can offer fiat money in return for cryptocurrency, which is done by <<bitcoin_price>> and selling to the wallet user at or above this price. The _Buy Bitcoin_ button would allow Alice to purchase Bitcoin in this fashion.
 
 Alice is now ready to start using her new bitcoin wallet. ((("", startref="GSquick01")))((("", startref="Wquick01"))) Her wallet application randomly generated a private key (described in more detail in <<private_keys>>) which will be used to derive bitcoin addresses that direct to her wallet. At this point, her bitcoin addresses are not known to the bitcoin network or "registered" with any part of the bitcoin system. Her bitcoin addresses are simply random numbers that correspond to her private key that she can use to control access to the funds. The addresses are generated independently by her wallet without reference or registration with any service. In fact, in most wallets, there is no association between a bitcoin address and any externally identifiable information including the user's identity. Until the moment an address is referenced as the recipient of value in a transaction posted on the bitcoin ledger, the bitcoin address is simply part of the vast number of possible addresses that are valid in bitcoin. Only once an address has been associated with a transaction does it become part of the known addresses in the network.