In my area, a seller typically pays his agent 6%, which that agent will split with the buyers agent.
It would benefit you to have someone to guide you through the process and help you protect your best interests and though the seller isn't willing to compensate your agent, you are perfectly free to hire an agent on your own to do just that. Commissions are negotiable and I bet that the agent you choose will be willing to represent you for between 1% to 4% of the purchase price.
It is not unusual for the seller to pay all the closing costs -even when they are willing to pay a commission, it all depends on your offer and the offers of any competing buyers. Your agent can help you write an offer that makes sense and maybe even show you other homes that you may like even more than this one.
Best of luck,
However, using a person trained in the procedures to guide the transaction to closing is a best practice, since it minimizes the occurrence of errors and misunderstandings. Those can be more costly than having untrained people try to avoid paying for assistance.
If the property is not listed, then you can choose to have a Realtor represent you without having the seller pay for it. You, as buyer, can negotiate with your Realtor a reasonable fee that you alone will pay.
If, on the other hand, the property is listed, then the seller won't be saving a dime because listings in MLS contain a co-brokerage fee the listing broker offers to other brokers to bring a buyer like you.
He's actually not saving anything. Chances are he's losing a buyer and will end up with nothing. If the property is listed with an agent now, they have a contract and he will be obligated to pay not only his agents fee, but a buyer's agent fee as advertised.
If the property is not listed, then you might want to discuss the best way to deal with this with your agent. Unless you have bought and sold many homes, know all the ins & outs of inspection, appraisal, title, current valuations, etc, do not consider buying without a professional representing you. He may not want to deal with your agent because he is hoping to take advantage of you. Don't let that happen.