Well, you can, and no, you won't need to invest in barista-level syrups. You need only raid your candy drawer. To make a cafe-worthy mocha, use a piece of chocolate broken off from a Ghirardelli ...

Ghirardelli and Hollander make chocolate sauces ... You can buy the same brand of mocha syrup Starbucks uses. The Fontana line is what Starbucks uses, but it only comes in a huge container ...