Scenario #2: bleeding chips

So this is another constant frustration at O11, mostly due to the $100 max buyin.

I'll sit down at the table and run pretty card dead to start.  I constantly get hands like jq, 55, 78 std, etc.  I will get this hand like this in middle/late position, someone will raise to $6, get a couple callers, so naturally I call.  Somebody after me raises to $20, everyone calls, so now I'm priced in and have to call.  I'll whif on the flop, somebody bets, I fold. 

Or, preflop I'll call the $20, than somebody reraises to $50 behind me and gets a few callers.  Now I'm in a situation where I've already invested $20 with a small pocket pair or std connector, and it only costs me another $30 to see a flop with $200+ in it.  The problem is, I'm likely way behind, and if (when) i miss the flop I'm folding. 

I went from investing $6 w/a marginal hand to now having a $50 invested...I think to myself, "how the fuck did I get this deep in the hand?"  So how to you avoid situations like this?