First, did you know that nearly 2500 meteorites fall to Earth per year? Did you further know that only 3 yes three, are found each year. You might actually have one in your yard without even knowing it. You can distinguish a meteor from a normal rock by its "thumb prints", which are noticeable indentations in the surface looking like - thumb prints of course. These are created during entry into the Earth's atmosphere where the surface heats to extreme temperatures boiling and burning the surface material.
Meteorites composed of iron can value as much as $800 to $1200 for one the size of an apple fritter. Stone based meteorites are more valuable with chips as small as a golf ball valuing the same as the larger iron based one, $800 to $1200. A bread slice sized "space gem" of a meteorite called a stony-iron meteorite, sliced thin to expose the olivine crystals, can value between 2 and 3 thousand dollars.
Interestingly enough the least valuable, iron, actually only makes up 5% (about 125/year) of the meteorites making it to Earth but is easier to find due to it's outer black iron oxide crust that may also quickly turn to rust. Though more stony- irons arrive here than the iron type, it is actually the rarest to be found.
Stony-irons are sometimes sliced too thinly at 2-3mm instead of the proper thickness of 5-6mm. This can result in the crystals falling out and possibly being glued back in. Be aware this can reduce the value of your specimen as can the improper flushing and stabilizing of any prepared surface, thereby allowing oxidation to occur.
Some stone meteorites have been found to have amino acids, the building blocks of life, inside prompting the theory that life on Earth have been "seeded" by just such a meteorite. Also, a good-sized stone is often cut or sliced into many pieces for selling or distribution in the science community. This means if you find one digging the rose garden, you may well have found a true buried treasure that could enhance not only your collection, but your bottom line as well.