Roamless

Roamless gives you two ways to pay. Their pay-as-you-go option starts at $2.45 per gigabyte, while fixed plans run from 500MB to 20GB over 30 days. The RoamlessFlex feature is the standout, unused data never expires, so you don't lose money to unspent balances.

Roamless appeals to travelers whose usage fluctuates or who dislike wasting data before expiration. If you're doing a quick trip one month and a long stay the next, RoamlessFlex lets you bank data from the quiet period and spend it whenever.