Can I put the less expensive gas in my car?

You have to use the grade gas listed in your owners manual do you know what grade that is?

It depends on what's called for in the owner's manual. If 87 octane is sufficient, you won't gain anything by using 93. The higher the octane rating, the harder it is to ignite the fuel. That allows the engineers to design the engine for more power. The gas doesn't produce more power. Typically, higher compression engines, (raising compression is one way of increasing power), causes the fuel to self-ignite too early, and raising the octane rating prevents that. Not many engines require higher octane ratings today.

The higher the octane the slower the fuel with burn to explain it in simpler terms.