I agree with Krathos (sorry if i mispelled it).
You can build many FG farmers, having only half upped (more or less, having the essential upped) and then play dunno 30 FG matches, by onyl winning a few (5~10) you get high chances of at least 1 upped card, seel it and keep upping your FG farmer.
Then, its a long way to the top for Rock&Roll
(Rock&Roll =
)