Couple of different FFLS. An 01 DEALER FFL covers modern arms, but you must be IN THE BUSINESS to have one. Means business premises, zoned for business, sales tax ID #, business license etc etc etc. An 01 will NOT be issued for "personal use".
The other is an 03 Collector of Curio & Relics FFL (known as a C&R). This is for people that DO NOT intend to "engage in the business" of buying and selling firearms. Covers firearms that are 50 yrs old or older, OR- have been designated as C&Rs by the ATF without regard to age- as in ALL Winchester 88s, ALL Colt Woodsman pistols, etc. One page app, $30, good for 3 years, simple record keeping. DOES NOT COVER MODERN ARMS unless they are on the ATF C&R list. Your STATE may have additional laws that can be stricter, but not more lenient.
Most fun you can have for 30 bucks without catching something.