To farm BFG with liquidity, you'd need another token (e.g. BSW) so one way or another, it's either investing some funds or taking the gambling risk.
Recently I purchased extra BFGs but I'd be needing roughly 20 BSW before I get to pair them. So I'm staking the latter until I reach the minimum.
I highly recommend that BFG- BSW has a huge 406.10% I advise you to buy BSW it's still cheap, all the other pair with very high APR are paired with BSW, there are a lot of strategies that you can employ when you have BSW, you can add liquidity or directly stake it, which I am doing right now, which is 609.11% APR one of the highest so play on Betfury to gain more BFG token then buy more BSW and stake to gain more BSW.