There are LOADS of oil brands competing for your money.
You can read in your owners manual and it will tell you what you need. Or you could listen to someone who knows a thing or two about engine oil.
Your Prius needs an engine oil that can withstand all the stopping and starting that happens. This cycling effect causes oil shear which leads to oil breakdown.
An oil that is built with a better and more pure base stock will help keep your Prius operating smoothly in between changes.
If you are in to DIY and change the oil in your Prius, you can count on Pennzoil to give you exactly what your Prius needs.
API Grade SN which is the current standard is what your Prius calls for. IF Pennzoil isn't your flavor click the link and you will be directed to other options to choose from.
With proper oil sampling you can go anywhere from 5,000 miles or more.
(*going more than the recommended oil change interval is no recommended unless you are sending in oil samples for analysis)