Subway Card--which one to buy?
 

We will be in the city for approximately 3 days. Staying at 37th and Lexington. We plan to use the subway to go the to museums, Brooklyn, LES, and downtown. It seems as though the pay-per-ride card may be the way to go as I'm not certain we will ride more than three times per day to go over the $7 for the unlimited.

If you buy a $10 Metrocard, you get 6 rides instead of five. This card can be shared, so one of you can go through the turnstile and then hand it to another. This card is ostensibly for seven days, but I got one last week that had a 30 day expiration date.

Purchase one pay-per-ride card for $20 and get 12 rides (2 free). If there are 2 of you, you can use the same card and ride 6 times (each).

Better than buying 2 unlimiteds.

Well both answers above are right, but the real answer depends on your itinerary and how much you like to walk. The most logical options are

>2 x $10 pay as you go metrocards--allows you to split up (assuming you're 2) and not be joined at the hip, gives you each 6 rides.

> 1 $20 pay as you go (same # of rides but you have to be together)

You can add money onto either of these options. If you think you're going to have one day where you travel a lot more (like the Brooklyn day) than the other 2, consider an unlimited card for that day and maybe a smaller amount card for the other 2. Don't make yourself crazy though. We did that in London and it's not worth the angst. ;)

Whn you buy a $10 "pay per ride" card (or any card over 10 or more) the bonus amount you get makes each ride come out to $1.67, not $2.00. So, 4 rides a day (not 3) still comes out to less money than an one day unlimited ($7) card.

Don't forget that you can also get one free transfer to a bus within 2 hours of when you entered the subway.
Sounds like the pay per ride will work fine for you.
One correction:
happytourist: the pay per ride cards have expiration dates of at least ONE YEAR from when you buy the card, not one week or one month.

I would recommend buying only $10 ($12 value) card.

We bought a $20 ($24) card for a four day visit and had $12 left over.

You can always add more.