Is it possible to find a good deal using an agent? That's exactly the reason why you want to use a Realtor when you are looking for a property, whether it is your home or investment property.
A good deal on investment property is relative to the area you are in; and yes, you can find great deals now in the Bay Area, especially if you have an agent who helps you do the search and leads you to the best property. .
They have the knowledge of the market, the inventory, what are selling now, and what are stalling, How to make attractive offer, how to talk to the listing agent, another middle person to negotiate the best deal for you.
Many times, FSBOs want to get the most for their money (saving commission, priced high and then they eventually go with a realtor), you really don't get a good deal buying through them and you bear all the liability that come with purchasing a property on your own.