The latter is going to cost much more $$$ and you have to actually be in the business of buying/selling firearms. The ATF frowns upon people acquiring their "class 3 license" to enhance their personal collections, and you will likely be prosecuted for tax evasion.Do you mean you want to become a dealer or you just want some class 3 goodies.
If it's the last one then not that hard. You have to find somebody with what you want talk to them about buying it. Then fill out a form 4 take it to your local CLEO to get approval as well as fingerprints taken. Then you need two passport size photos, a $200 check or money order, then send it in and hurry up and wait 4 to 6 months. But if you want to become a dealer then you have to get your 01 FFL and "01 SOT" I think it's the 01 Sot, but it might be one of the other two.
check out FFL123.com
It's a good informative site and you can purchase the 'do it yourself kit' for obtaining your FFL license. This guy leaves nothing out of the equation and gives you a step by step easy to follow map of how to do it.
Most folks here who are C-3 dealers will tell you that paying anyone for any kind of "kit" is a 100% waste of money...