With free Wifi everywhere these days, there is absolutely no reason to meet 'at your office'. Common, that's just outdated mentality. If you're just starting out, spend hundreds/thousands on office space is just crazy talk. It would be a total waste of money.
Meet at Starbucks would be just as convenient and comfortable for most clients. And beside, you would usually be the one visiting your clients (so you will be going to their office/shop).
Of course, once your business expands, then its a different story. But having an office space is definitely not a requirement for a tech/marketing startup these days.