This was good timing, since we just completed our first comprehensive update of the pool scene for the 2014 season. We say "first," because things have a habit of changing as the weather heats up, regular parties and concert series get underway, and space is at a premium. Early on, when the weather's still hit-and-miss and only the hardiest (or foolhardiest) are out lounging, a number of pools operate an extremely relaxed admission policy, often letting anyone in gratis. But with Spring Break upon us and Memorial Day Weekend looming, the hotter tickets in town may start excluding non-guests, or else charging a stiff cover (unless of course, you're a nubile hottie yourself, or better a group of same, in which case it's pretty much open season all-summer long).
We should make the point that in general, pool-admission policy has become more and more liberal over the span of the past half-decade plus that we've been monitoring the scene closely. This may well stem from the overbuilding frenzy that coincided with a drop in visitation as the economy crashed, leading to a desperation for bodies in general. There are a lot of party pools competing now - Rehab, Wet Republic, Liquid, Bare, Daydream, Palms, Tao, Naked, Venus Pool, Marquee, Encore Beach Club, Daylight, The Voo, Sapphire Dayclub - plus just more pool inventory in general, and it seems to be an instance of this working in the interests of the customer at least in terms of accessibility. (A few instances aside, there's no indication of any commensurate drop in cover charges where they apply, however, especially for males; on the contrary, Moorea Beach and Wet Republic are now charging guys up to $75 entrance on the weekend!)
Our "Open to the Public" listings in the Cool Pools section (click the icons in the legend to sort by specific amenity) include those open for free, or a nominal fee, but also those that host major parties and events and are open to all for a cover, so many will be included in that search that don't fit your "modest-charge" criterion (which we're interpreting as meaning $10 or less, occasionally stretching it to $15). What follows are those venues which we can confirm fit the bill at the time of this writing; again, things can and do change overnight, so call ahead before you make a special journey somewhere (and if you can't speak to someone at the pool itself, ask for the spa, as they generally will know more than the front desk or concierge, from our experience).