Yes,
But I am more familiar with Coinbase.com, there you can buy/sell/send/request bitcoins.
It is set to the local currency of your country, and you will have a wallet automatically. The wallet address is found in the account settings/bitcoin addresses. The website automatically creates a bitcoin wallet address every 9 days. Don't worry about that, you can use any or the same bitcoin wallet address for forever, so it doesn't matter if the website keeps creating a new address, the address that you use to receive is reusable.
Goodluck. If the site like you mentioned, coinjar.com is a bitcoin exchanger, yes, they do have a wallet system where you keep your bitcoin balance. The good thing about that is that you don't have to backup your wallet offline because the site backups wallet for you. Like in coinbase.com they backup everyone's wallet offline and update the balance everytime you make a transaction.
Hope this helps.
what I am was trying to ask, being a bitcoin exchanger - how do they handle the situations when I ordered to buy 10BTC at 400 via their website, and paid them 4000 + some fee, but they will only forward my order after they receive my money (4000 + fee). If by that time the price of 1BTC is 450 - they simply would not have enough money to buy the amount I ordered. How do bitcoin exchanges deal with such situations? – Mitten – 2013-11-16T16:12:44.437
1@Mitten: They don't. A Bitcoin exchange won't let you place an order before you have the needed funds deposited with them. (Perhaps as a usability feature they will allow you to place an inactive order that will activate when you have funds.) Anyway, the exchange doesn't "buy" bitcoins, they let you buy from someone else who wishes to sell. Note that there are services that work differently from exchanges. – Meni Rosenfeld – 2014-07-16T20:09:34.053