You can try to buy BTC with PayPal or some other service here on forum, we have Currency exchange board, but in case you do that be very careful and trade only with trusted members (check their trust ratings).

When it comes to crypto wallet, you can download something like Electrum, but always check that you download from official site, and try to learn how to verify files signature. If you think seriously deal with cryptocurrency consider to invest in hardware wallet (Ledger or Trezor), it is much more safer way to keep crypto then any desktop / mobile wallet.