If you’re in an area with fairly good Sprint coverage, for example, you can use Virgin Mobile’s 18c/minute plan (which includes long distance, and no fees or taxes other than sales tax). Average monthly cost (assuming 50 minutes): $9 plus sales tax.

Or, if T-Mobile works better for you, for $25 you can buy a 130-minute block (or a 150-minute block once you’ve reached Gold Rewards status). Average monthly cost (assuming 50 minutes): just under $10 plus sales tax.

On either plan, using more than usual is no big deal: you just buy more minutes, at the same low rates (instead of getting soaked for 45 cents a minute as with the Verizon plan above.) There’s a minimum purchase to keep your account active, but it’s pretty low ($20 per 90 days for Virgin, $25 per 90 days for T-Mobile) and your unused minutes can roll over (with Virgin, they keep rolling over as long as your account is active; I don’t know T-Mobile’s terms as well).

Verizon has prepaid plans as well (as does AT&T), but the terms weren’t nearly as good last I checked. (Verizon’s in particular had high daily charges and other gotchas.) Still, if that’s the only network that works for you, they may be worth comparing to the contract plans.

If you’re not sure whether other networks work well or not, though, you might want to give the Virgin or T-Mobile plans a try. If they don’t work well in your area, all you’re out is the cost of the phone and the minutes you’ve used, which can be less than just the activation charge on contract plans like Verizon’s.