Hi!
The price and tips really depends on where you go and what you’re doing. Usually you can get discounts for longer hires. Whether you buy a meal is up to you.
Before I answer, it would be good to get more information. Will you be sticking to the Central Valley or traveling to the Pacific coast, Arenal, or other area? Would you like the driver to also be a tour guide or just get you from place to place? Would you like someone knowledgeable in real estate? Will you stay overnight anywhere else? Are you okay being in a group with other prospective expats or do you prefer it be a private tour? Are you interested in hiking in national parks or a similar activity?
Let me know. What might work best for you is a combination of private driver, tour group, public buses, private shuttles, and other resources – it all depends on your answers. And i’m happy to help you put a plan together.
By the way, I would recommend you visit Kay’s Gringo Postres soon after you arrive in town. This is THE expat hangout in Atenas and I’m sure you could get a great recommendation from the owners, Harold and Lisa Beasley, or the expats who are there for drivers. And they can tell you all about life in Atenas too.
http://www.facebook.com/kaysgringopostres/info?tab=overview