Get Bitcoin wallet.

If you already have Bitcoin wallet then good.

Coinbase and block chain would be best in this and other like xapo. You can find more wallet here bitcoin.org

As bitcoin is getting popularity these days most of the trading and exchange companies and including Bitcoin in their features so no one has to look other. Here you get trust buying or selling.

There are still online stores which have no option to pay in bitcoin.

Payza an online payment system similar to PayPal has now introduced Bitcoin wallet. So one can exchange it easily without going to others as a few years ago we all had a question how to exchange BTC into USD. Now it seem to be possible in a single place.

eToro has already announced digital investment including BTC and etherum, soon other will be added.
----Online Best Payment Systems - wall-spot