The unfortunate but true answer to the question, "what items should I buy?" is that it greatly depends on your hero and playstyle. Every single guide, whether written with newbies or advanced players in mind, has critics. No matter the guide, there will always be someone who disagrees with the guide.
Here are some general tips to help get new players started by keeping the game moving and not spending valuable in-game time browsing the shop.
Spending your starting 603 gold Edit
This will spend your 603 gold exactly. This starting item selection will boost your all of your stats by 5, while giving you enough restoration items to hold out for a while before having to return to base.