We are visiting several NP (GC, Zion, Bryce, Arches...) and I am considering which is the most convenient fee for us. By now, I guess that America The beautiful pass would be the best, because it includes both of us and ilimited visits. But I have one doubt: does it include shuttle services or we will need to buy another ticket for them? (for example, shuttle bus service at Bryce Canyon).

If you like visiting the national parks (and we love to) that pass will save you a lot of money. We've been amazed at the prices we DO NOT have to pay to get into the various parks.

The shuttle busses at the national parks are free as a way to help control traffic congestion. Your America the Beautiful pass will get you on the bus and into the park. We noticed that the entrance stations requested my driver's license with the pass to enter the park.

Many thanks to both of you. Another mark on my trip planning.
Shuttle bus will be very convenient for me, because I will only be able to do very short and easy hikes...

the America The Beautiful Pass is now $80 and good for a whole year from the month you purchase it. Grand Canyon is $25, Zion is $25, Bryce is $25, Arches is $10, so you will save $5. If you are also going to Capitol Reef it's $5 and if you go to Canyonlands, that's $10. So the potential to save a few dollars is there.

And as mm_mn has mentioned, the shuttle buses at the Grand Canyon, Zion and Bryce are free.

Utahtea

Hi, Utahtea:
I don't think we are visiting Capitol Reef, but Cannyonlands is a place we would like to include if we have time enough (which I doubt...).
Too many gorgeous places in Utah!!!

Wow, the pass is up to $80 now? Yikes!! But I guess that's nothing compared to the price of gas.

There is a $10 pass for those over 62. FYI only, not to indicate that you might be able to get one
EDITED

While the America the Beautiful pass is more expensive than the old National Park pass, it covers more than just the national parks now. It also covers national monuments now too.

It always covered National Monuments, but you had to buy the Golden Eagle sticker for it to cover National Forest and other Federal Recreational Lands.

The entrance to many of the parks like Yellowstone, Yosemite, Grand Canyon, Bryce and Zion have gone from $20 to $25, so the new pass is still a good deal if you plan on visiting enough parks in a 12 month period.

Utahtea

http://www.doi.gov/parkpass.html

This DOI site has the Park Pass information. Worth it if you visit often or if you visit many of the Parks..

Price of the gas? I don't think it is a problem for us... but how much is the gas now at the States?

You may save money with the pass and you may also save time. A lot of the parks will have separate entrance lanes for pass holders.

AND the new pass covers BLM parks, National Recreation areas, and National Forest areas. This is nice if you, like many others, for instance, make Las Vegas an entrance/exit/base for the Utah/AZ parks and want to visit Red Rock Conservation Area. It's a BLM park, costs 10$ to do the scenic drive, and you're covered with the pass. Just another benefit.

Does the Natural Bridges national monument accept the America the beautiful pass????

All federal lands passes are issued and accepted at Natural Bridges.

You must sign the America the Beautiful Pass on the back side. You must present the Pass along with proper signed photo ID to enter.
I bought my Lifetime Pass for $10 at the visitor center at Crater Lake. It was late October and the north entrance was closed due to snow. There was no one at the south entrance to collect fees.
When you put up the Pass in a hanger on the rear view mirror or dash, you put your signature out to be seen. The Passes are serial numbered so they can find out who you are if they can't read the signature.

Two people that I worked with got married, and I gave them a Park Pass as their wedding gift, since their vacation plans included Grand Canyon. When they returned from their honeymoon, they confessed that they didn't know what it was I gave them at the time; thought it was some sort of chintzy discount card.

Then they got to the entrance of the Grand Canyon, and cars were lined up for quite a ways. They got in line. A ranger was walking back along the cars, screening for pass holders. They asked if this gave them some sort of discount..that's when they were told what it was and waved on to the passholders entrance (no line). They completely changed all their vacation plans and spent the next two weeks visiting all the national parks in that part of the country.

By the way, the Canadian Park Pass is quite a bit pricier - $136.