Costs will vary substantially, depending on how much recent survey data is available. If you have a survey for the whole parcel, for which you are breaking off a piece, you should use the same surveyor, It will save you a lot of money because they already have survey "control" over the land.
If it is significant acreage, you might want to ask if there is timber value before selling. If so, you can include the timber value in the listing info.
A good real estate attorney will not let their client close on the purchase of land without a survey. This is usually a Seller expense.
You have some good info so far. I am curious, why do you want to wait to talk with a Realtor? I can understand that you want to be learn what you can before you sell, so why not pick the brains of a Realtor with experience selling vacant land?
In truth, land development is a horse of a different color. The survey and engineering can take a year or more, is very expensive, and will take a lot of your time. That's why talking with the individuals recommended by our previous poster make sense, however I think an experienced Realtor would be my first stop.
There are many variables, but time is money, so I would begin your investigations as soon as possible.
Mario is right - You need to talk with your local Planning Dept. to find out what are permissible uses for your land. Determine if your land is a buildable lot, and if so, is it subdividable.
Browse your local real estate listings and see if their are some realtors who specialize in land. You can also ask for a referral from your real estate attorney. Town hall employees generally cannot make referrals to Realtors, but you might be able to find out at town hall which Realtors have listed land and subdivisions before.
If the land is subdividable, you will need to decide if you want to do the subdivision or sell the land to a developer to do a subdivision. Doing the actual subdivision would eventually bring the most return. However, this is generally not feasable for most non-professionals. You would need to have the ability to work the project throught the whole subdivision process and then build the infrastructure e.g. roads & power. Generally, it is more practical to sell the land to an experienced developer who has the ability to do the subdivision and infrastructure.
However, you will get the most for your land from a developer if you have done the basics such as survey and possibly some soil tests. Land is always much more saleable if it is surveyed. If you do get a survey, try to pick a Survey and Engineering firm that handles subdivisions. To find out who does that, you can ask your local Planning Dept., or watch one of the Planning Review Meetings.
But before spending any money on survey, I would then talk to 3 local Realtors and see what they have to say.
So, if I had sizable acreage, I would talk to the following professionals before listing my land: (1) Local Planning Dept., (2) Real Estate Attorney, (3) Local Survey and Engineering Firm, (4) at least 3 local Realtors.
This is my non-professional advice. I am not a Realtor but have done a small subdivison. You are on the right track by asking questions upfront. Best of luck to you.