Agents typically only take a commission on buying or selling a property. There are some agents that also have their own investments. If you were to "partner" on the investment side of things, treat that like any other partnership with the benefit that one of you has a license. Outside of that, just work with agents to buy and sell properties.
As far as "deals" go, that is a misconception. Agents don't have a long list of hidden deals that they are holding on to. As a listing agent on a property, the fiduciary duty is to the seller and no one else. Your duty is to sell the property as soon as possible and "net" the seller the most possible during the transaction. The agent isn't looking to give any buyer a deal in that scenario. Some people "think" they can get a deal by going to the listing agent, but that is a false notion since the agent isn't there to create deals for buyers, they are there to protect the interest of their seller.
One exception to this would be if a listing agent alerts you about an upcoming listing before he/she puts the property on the market. But this only happens if the agent actively looks for new listings. A similar exception would be if you have the agent look for specific types of properties and approach those owners about selling their properties before anyone gets to them.
On the buy side of things, the agent is there to help buyers find and research properties, submit offers, coordinate the inspections and appraisals, field questions where needed, and ultimately make sure it gets to the close...
The agent will get you the information you need to help analyze the deal. At the end of the day, what you are willing to "offer" as an investment should be driven by the numbers. That should be clearly stated with the agent. Buyers have problems with agents when they are not transparent about what they are trying to accomplish. Don't create an adversarial situation with your own agent, they are there to work for you. Communication and transparency are key.
There are two type of buyer goals: home buyer and investor.
If the goal is to get the house at any cost (withing budget of course) because you want to live there, the agent is going to try and offer what has the best "chance" of being accepted. In a seller's market, you have to be quick to see the property and quick to put in an offer. What that offer should be should be based on research (average days on market, absorption rate, sales price as a % of list price for the area, seller motivation/situation, comps, condition of the house, other variables). However, sometimes home buyers try to treat this like they are buying a car and want to negotiate for sport. In those situations, they often have to lose out on a few deals before they learn the hard lessons.
As an investor, you can't operate that way. As an investor, you have to protect your profits and that means you have to be willing to walk away from a property if the seller is unwilling or unable to go lower than list. As an investor, you really should be sitting down with your agent on a regular basis to discuss deals and strategy and make sure everyone is on the same page.