A lot of variables for that, size for instance. See what the going price is at stores. Generally, hobbyists selling corals will have to offer a tad cheaper and rightly so since they are not paying for expenses to run a business. A tad cheaper is what makes buying from hobbyists appealing. However, if you plan to ship then a hefty overnight shipping charge will come in to play. Which is why most people won't shell out that much for shipping one single coral.