Virgin Mobile has announced that starting next month it will offer an unlimited calling plan starting at $80 a month. Like the other calling plans the company offers, the new one will be pre-paid, so there will be no need to sign any contract.

The new plan, which Virgin Mobile has dubbed ‘Totally Unlimited,’ will allow users to have unlimited calls at the price of $80. This, however, doesn’t include free text messaging or e-mail, for which people will have to pay an additional $10.

The move means that Virgin Mobile will join the four largest players on the market, AT&T, Verizon, Sprint Nextel and T-Mobile USA, which started to offer flat-rate calling plans at the beginning of 2008.

Virgin’s offer is interesting because of two main reasons. First of all, it is the cheapest flat-rate plan on the market. To make a comparison, Sprint and T-Mobile sell their service at $99.99 a month, while Verizon charges from $99.99 to $139, depending on how many options one wants to add.

Second of all, Virgin Mobile doesn’t require its subscribers to fill in any contract with the company, thus making it ideal for people who don’t want to be tied to the same provider for two years, the average period of time that the four big wireless carriers close their contracts on.

Virgin’s new plan might make the company get over the harsh times it has experienced recently, as last month the company’s income has seen a 75 percent decrees. Virgin will also become the first mobile virtual network operator in the US to offer this kind of plan.