You need to be careful when taking the advice of agents. Listing or selling agents make there money from the SALE of your home. They will do waht it takes to close the deal. With that said, both of the answers above are technically correct. It may be common for buyers to ask for closing cost help but from your point of view you might as well just decrease the sale price of your home. If the buyer needs closing cost help because they don't have the capital, I suggest helping them with these costs but increasing the total sale price. In effect, this allows them to build the costs into their loan that is repaid over 30 years. You still get your money now.
As for commisions, agents serve an important role in real estate for many people but as the seller be aware that you are the only one that benifits from keeping the price up. For example, if you are advised to accept the additional terms of paying cosing costs of, let's say, $5000, you loose $5000 and your agent still gets the same commision. If you adjust your price up, as I suggested, you get your $5000 and your agent gets an additional $150. That seems like a benifit to your agent but more than likely your agent is more interested in ensuring that this sale goes through so they get their 3% on the whole sale. Jepordizing thousands of dollars for an additional $150 does not make sense.
This answer will not be popular with agents. Just remember you represent you!