You can not become an FFL solely for collecting or purchasing firearms for yourself. It has to be a buisness to buy and sell firearms to make a profit.
Your local ordinances may be the biggest hurdle. I wanted to become an FFL but my local ordinances provide that you have to have a storefront - not in a residential area - to comply with the law.
This sucks because I wanted to re-manufacture ammunition, not sell firearms, and got caught up by the ordinance.
Your best bet is to check with the town/county that you would be operating in to find out what hoops you have to jump through. After that, its an easy process with the ATF as selling one gun a year (not yours - the buisnesses) and making a profit will comply with the law.