I recommend using an agent if you have basic questions about realtors. Only because that means to me you probaly do not buy and sell houses often, and a realtor can help you through the process, but it is not necessary of course. If you advertise the house yourself, you will still want to cooperate with a realtor for the buyers side, because in this market you cannot hold out for a buyer wihtout a realtor. You can offer the buyers realtor whatever you want a perentage a flat fee, whatever. But, I would say offer them what ever seems to be average or better in your market. So, if most realtors are requesting 6% for a listing, probably offer a buyers realtor 3%, if it is a house under $150K maybe go higher. Have a lawyer look over any contract handed in if you are not familar with sales contracts. There will be requirements for you to fix things, there will be contingencies for the buyer to be able to cancel, make sure you feel good about whatever you might be signing. Realtors can expain these things to you, or a lawyer.
Realtors will get your listing into the MLS, which automatically puts it into realtor.com also. They have to pay to upgrade the realtor.com listing, which means showing additional photos and some other enhancements.
They also can put it on lockbox, if you are ok with that, so the house can be shown at anytime. Easy show makes it more likely to be shown. If the house is not convenient for you to check on and no one is living in it, the realtor can do that for you.
Housing generally sells for what the market is willing to pay. It’s true that realtors are more interested in closing a deal than getting you an extra $10k for your house; but, good ones also care about you, long term business relationships, and referrals. Many will treat the sale as if it was their own home, some won’t, like any business deal.