Yes, agents can be very helpful in many situations, but be aware that they very rarely get involved in the mil players dealings with the team. Once the player gets to ML that can change and does.
Agents do not do anything for free. Players drafted using an agent pay a fee for their services not BEFORE the draft but after they become professionals. That fee may cover many things. Sons agent was and still is instrumental in getting him endorsements, equipment, as a new signee card deals, etc. There are some other perks, example being the agency does his taxes for no charge, part of the service that they provide their clients. Since sons time as a professional has been complicated by injury, agent has been very helpful in advice and medical contacts and recently negotiating a FA contract. However, the next time he will ever see any money from son will be if he ever goes to arbitration as a ML player. That is really the only time one really needs an agent (for contract negotiation) and one who knows the business and has negotiated contracts for others in the past.
Be aware that if a player secures an agent after the draft, many usually ask for a yearly fee, which is understandable if he is to get him things that the player would normally pay for.
Every spring training the companies visit all teams, at that time players can pay reduced fees for things like bats, gloves, shoes, etc and make agreements. Sons agency does not supply pitchers with bats, so DK got a hookup with Louisville Slugger on his own. He also gave his extra stuff to guys with no agents, as many players do, to help others out.
One doesn't have to worry about finding a qualified agent, as the player advances and shows ability to possibly reach ML level, he will have agents contacting him and he can do the choosing, not the other way around.
Be aware that an agent that does not have a player on any 40 man roster (just has to be one), is not able to do business (negotiate) with ML teams, so be careful of the person who wants to be your players agent! You want an agent who is recognized by the ML Players Association.
I am not sure why you are asking but be aware that I am pretty sure that MLB does not allow agents to solicit newly signed players at the entry level.
I tend to believe what backstopdad32 has said, there is a lot of crazy stuff that goes on. There are many guys who take on guys and then they are never to be seen or heard of. Good agents don't do that, they stay in touch with their players no matter who they are, and visit them during spring and season.
BTW, the clubby most likely can give better recommendations on housing in the area the player will be residing in rather than an agent who lives in another areas of the country.
