For the airfares, you can go to these airlines' websites.

www.etihadairways.com
www.emirates.com
www.qatarairways.com

Airfares depend on when you're planning to vye for Qatar.

For the requirements, the best place for your queries would be the Embassy of Qatar in Makati. Also, this one depends on what type of visa your friend will get for you.

As for the pocket money, it really depends. Cost of living is a bit expensive here as opposed to our cost of living there in the Philippines.

Hope this helps.

Cheers! Hope you enjoy your trip.