THE BRONX - Riders who toss their MetroCards after use may want to think twice.

The Metropolitan Transportation Authority unveiled a 2012 budget that doesn't cut service or hike fares but does tack on a service fee for MetroCards.

Riders would be expected to pay $1 each time they purchase a new MetroCard. The surcharge is intended to encourage riders to refill MetroCards instead of buying new ones, which will reduce MTA expenses on production, sales and cleanup.

The combined savings and revenue is estimated to total $20 million, according to the MTA.