I've used the textfree app for years, it used to be the pinger guys (actually, they have started to move back to the pinger name/brand) I often find the calls better than skype on some networks either due to skype blocking or maybe just better routing. You have to either pay for minute or jump through some download apps hoops to get a bunch of free minutes. It's also a great texting app for when travelling abroad. The downside I would say for texting is that there are ads (unless you pay to remove them) and the ads use bandwidth/data so when on a restricted foreign network google voice is better for texting..lowest kb's use.

But, the voice quality is very good and calling to any USA number works great.