I work on the engineering side of an engineering and surveying firm, but I've helped out on a few surveys, so I can offer a little advice. Almost all surveyors use GPS, as long as it will work in the area being surveyed. 90% of the work is establishing the first point, which would be a property pin in this case. Once that has be established, it's almost trivial to do the calculations to find the others and mark them as well. So I doubt you'll find someone who'll do one at 1/4 the cost, but on the flip side, if they're locating one, it'll probably be the same cost to confirm the locations of the other pins.
If you do get a surveyor, make sure they give you the exact GPS coordinates for each pin. The standard accuracy for GPS surveys, at least the ones I work with, is 1/10 of a inch. With exact coordinates, if you'd every need to reestablish a pin, the entire process would take another surveyor 15 minutes, start to finish, and be much cheaper as well. Additionally, you could find them yourself using a consumer GPS unit for much cheaper than a survey, as long as you didn't need to be accurate to more than about a foot.
Finally, if you're having problems with people vandalizing your pins or if you just never want to worry about locating them again, put in monuments. A surveyor can do that for you, for a very "reasonable" price, but they're really pretty simple to make and install yourself.
For materials for each one, you'll need a 1.5' - 2' piece of 6" - 8" plastic pipe, a bag of sakcrete, and a 2' piece of 3/4" rebar. First, place your pipe standing with one opening on the floor and one at the top in a place where you can leave them set for a week, once they're filled you can't move them until they cure. Putting plastic under them to protect what's underneath isn't a bad idea either.
Mix the sakcrete with water until it's about the consistency of cake batter, then fill up your piece of pipe. Embed your rebar a foot into the top of it so there's still a foot remaining past the concrete, then let it cure for about a week. To install, simply bury the pipe with concrete portion of the monument 2-3 inches below the surface of the ground, with the rebar being used as the pin above ground.
It takes some effort, but is very doable as a one-man job. Keeping the concrete in the pipe makes it easier to work with and prevents someone from smashing the concrete around the top of it and removing the pin. If want to be as accurate as possible, place two stakes approx. 4' off of the property pin before you remove it to place the monument and use them to triangulate the exact location for the rebar.
A standard monument is usually enough to dissuade anyone who would be inclined to mess with a property pin. Even if they break or cut the rebar at ground level, the other half that's encased in concrete and buried is a cinch to relocate with a metal detector or even a shovel, if you have good measurements. However, for ultimate in permanance, you could upgrade to a 12" corrugated plastic pipe, increase the length to 2' - 2.5', and use 1.5" - 2" rebar. The only way someone is making a dent in one of those is heavy equipment and/or contractor grade power tools. Of course, the downside is the increased cost of materials and it would be difficult to install as a one-man job.
Anyways, hopefully you can get something useful out of that info dump,
