We did...they have taxi's and taxi vans waiting for people. They wore uniforms and are regulated by the government on their rates, and I think we paid $50 for a city tour, but that's been quite a few years. The van driver had a cooler prepared with sodas and water for us to drink throughout the day. (free)
We drove to where the cliff divers were, and were able to get out and take our time watching them. There were small booths of locals selling tinkets, but our driver told us to not buy the "silver" from any of the booths, rather to wait until we went to an actual shop in town.
We drove all through town, admiring the gorgeous old buildings, and then we stopped in the main shopping area of town, while our driver waited. We could see him keeping an eye on us so that we didn't get lost...or maybe he didn't want us to disappear and not pay him!

In the center of town are a ton of shops, churches, and the marketplace where the locals buy their meat and other groceries. It was really interesting....and I actually felt better knowing our driver was waiting for us.
There were 6 in our group, by the way. I don't think they based the cost of the van on the number of people, I think it was a set rate.