One up front investment buyers should be aware of when purchasing a home is their down payment. How much you have to put down is based on the type of loan you're getting, how much you'd prefer to see in a mortgage payment, and how much you can reasonably afford to put down.
An FHA loan (Federal Housing Administration) has a mandatory down payment of at least 3.5%. This is a loan that is often used by first time home buyers.
A Conventional loan can be as little as 3.5% down, through some banks, and as high as you'd like to put down.
However, the real questions you have to answer are how much would you'd like to keep your monthly mortgage payment and how much can you afford to put down. Based on these two answers you'll know what you need to prepare for.