Want to Accept bitcoins from php form I want to exchange BTC with other payment methods on my website. 

person A will fill the form with email, name or other required fields and then fill amount of BTC he want to exchange. that form will take him to payment form (like Paypal checkout form) after that, I will "manually" transfer him dollars to his bank account/paypal or any other payment service.

I've seen Paypal integration, and I've tested it with my sandbox account. but I don't find any tutorial for bitcoin.

I tried to use blockchain but for API they require website URL and currently I am developing on localhost.
Block.io is pretty easy to use, but their free api is limited.

Blocktrail is another option that is easy to sign up for, and relatively easy to use as well.

My personal favorite is still blockchain.info but you are not the first one to mention difficulties getting an API key. 

I've noticed the same lack of tutorials for Bitcoin web development which is why I started my site and youtube channel 2 years ago. If you Google how to use block.it api or how to use blockchain.info api you should be able to find tutorials that will help you.