FWIW, Griz, @ ~4k hands (not a lot, I know), I have a VP$IP of ~22%, and I've been cranking out a modestly net-positive BB/100 (~4.00). Of course, probably about a third of those hands were played at shorthanded / 6-max tables, where you really do have to loosen up a bit (not something I'd suggest if you're just starting out!! I've since moved back to full tables.), but I think in a really loose game, as long as you're careful about *how* you play some of the more speculative hands, a VP$IP of just a bit over 20% is within 'tolerable' limits... You do have to be careful, as you've already observed, to not cold-call raises unless you've got strong hands. And, really, if you've got a strong enough hand to cold-call a raise (e.g., high pairs - TT thru AA - or big aces like AQ, AK), you'll probably want to think about raising.
Personally, I think it's tricky whether or not you want to raise with TT/JJ or even AQ - but those are hands that I'd usually cold-call with from middle position or later. Whether or not I raise really with those hands depends on the situation.
But the point is that with hands that are weaker than those big pairs and those big aces (i.e., your top money makers), it becomes very difficult to justify a cold-call unless there's plenty of action in the pot. I would say with at least 12 small bets in the pot, you could probably start to play some of those weaker pairs or the weaker suited aces, because you are going to be getting 6:1 on your money to see a flop. With a decent hand like ATs down to even, say, A8s, and with pairs from 99 all the way on down, you're getting pretty decent value on your money. You just have to be ready to ditch the flop if you've completely missed it. This is where playing from a later position really affords you the advantage of seeing what kind of pot odds you're getting before deciding to chase; this is also why it becomes very difficult to be able to even just limp with some of these marginal holdings.
I'll say one more thing about speculative hands - and that has to do with limping. If a lot of people have limped before you (7-8 people), and you only have to call 1 bet, you can probably very safely see the flop from late position with even just a suited king, I think. I think you've got to be prepared to throw it away right away if someone raises and people don't continue to call the raise - but the key here is pot odds. Pot odds, pot odds, pot odds! I don't think there's very much you can throw away when you're getting crazy odds like 12:1 or higher - as long as you've got outs, you can continue to draw. You just have to watch your odds, and watch the class of players you're up against, and I think you can play some of these speculative hands for +EV.
I think a great reference on these super-loose types of games is Small Stakes Hold 'Em by Ed Miller - he describes exactly how you should count your weak drawing outs, and under what situations you can cheaply see a flop. If you haven't also read Winning Low Limit Hold 'Em (Lee Jones), that's a good introduction as well.
One final word of caution: all of this advice really only applies to those super-loose games with weak players. The minute you start getting the LAG-types in there, you have to be much more careful to not throw your money into every pot, because that *will* be -EV. (If I'm not mistaken, I think that's precisely their strategy!)
OK guys - am I wrong here? Please correct my thinking!