When to play any two cards / very marginal holdings...

So lately I've been thinking a lot more about pot odds, and times when it may be worthwhile to come in with just about any two cards.

For example, at some of the cheaper $10NL games I've been playing, the blinds are .10/.25. Often, I'll have some crap like Q8o in LP. There will be 5-6 callers, and it comes to me.

Should I call .10 into a pot of .60? What about .50? At what point are pot odds good enough to call about anything?
1:5, 1:6, 1:7, more?

This also happens fairly often in home games with tables of 8 and .25/50 blinds...

Say, 4 people call making the pot around $2, and it's .25 for me to limp with crap. Should I getting about 1:8 ?

Love to hear your thoughts...