Are you looking to buy a business, or to sell a business? When you buy a business, there are two different methods; you can either buy the assets (and sometimes debt) of the business, or, you can buy the common stock. Before you can make a good decision about this choice, there are a variety of issues to address.
How you handle the purchase or sale will have tax effects, but also financial and legal ramifications. You need to address your unique situation with someone who will actually care about what is best for you.
The buyer and the seller have to agree on the method of sale. Further, in the case of an asset sale, they have to agree on the allocation of the purchase price. There can be benefits to the buyer or seller to allocate the purchase price in a certain manner, but such an allocation may not be beneficial to the other party. Thus, these issues need to be addressed upfront with an advisor who you trust and have a good and comfortable relationship with.