Trying to purchase a Cafe

You can only buy retail stores and restaurants . If you want to make a bakery, you buy a retail store and get the appropriate items and sell baked goods. You can add a coffee maker into it, but you won't get money from it, sims will just make it themselves. IF you are hell-bent on owning specifically a Café, I'd suggest this mod: http://modthesims.info/download.php?t=592824. Please read through it if you take this route though so you know exactly what you're doing.