Cash and trade, but a lot of the value to get the current games were made by trading and then selling off the trades.

PM - cash
MC - cash
Avatar LE - cash
AMH - cash
RZ LE - trade
Transporter - trade
Alien - trade
Radical - trade
USA football - trade
eatpm - trade and currently spoken for in another trade

The thing with trading is it works best if you are open minded about what you are getting or you offer a lot of people.

My latest round. Bought a lah that had been in a fire and had the boards stripped. Got boards from a friend. Sold the game to another friend and used the funds to buy a ripley's with moisture problems. Dealt with the moisture, but didn't fix the game and offered it for trade. Best offer was an eatpm straight up, but had to drive 3 hours each way to get it. Swap the displays in eatpm due to issues and offer it up for trade something like 10 times. Get a hit on the current trade.

Persistence is key and knowing when a trade is fair or in your favor. Get offered a lot of bad trades where I'd lose my shirt and just gotta walk away. I'd say for every dozen trades I discuss one happens. It does allow you to get stuff you'd never otherwise be able to just buy though. Previous one before that was trading my houdini for a transporter. Not a game you can just buy and tradewise it was even minus a display issue I had to fix, but I got a game delivered to me that you could spend months looking for.

Oh they can be, but sometimes people will offer up. Before the recent round of lebowski's came out I was seriously sitting down trying to figure out what games I'd offer to trade someone should one get posted. Would have taken a good chunk of my collection, but was seriously considering 15k worth of hard to get games to let go of.